Fungus Flora of Tropical Africa

Volume 2

 

 MONOGRAPH OF LACTARIUS IN TROPICAL AFRICA

 

by  Annemieke Verbeken & Ruben Walleyn


Plates / Planches


Contents

 

Acknowledgements

Introduction

Material and Methods

Characters used for the identification of Lactarius species

     1  Macroscopical characters

          1.1  Basidiocarps

          1.2  Pileus

          1.3  Lamellae

          1.4  Stipe

          1.5  Context

          1.6  Latex

     2  Microscopical characters

          2.1  Basidiospores

          2.2  Basidia

          2.3  Pseudocystidia

          2.4  True cystidia

          2.5  Marginal cells

          2.6  Hymenophoral trama

          2.7  Structures of pilei- and stipitipellis

Distributional patterns

Abbreviations

Lactarius Pers.

     Brief history of Lactarius collections from tropical Africa

     Practical key to sections of the genus Lactarius in tropical Africa

     Sect. Lactariopsis (Henn.) Singer

          Key to tropical African species

          Species descriptions

              1. Lactarius annulatoangustifolius (Beeli) Buyck

              2. Lactarius zenkeri (Henn.) Singer

              3. Lactarius pelliculatus  (Beeli) Buyck

              4. Lactarius heimii Verbeken

              5. Lactarius velutissimus Verbeken

     Sect. Chamaeleontini Verbeken

          Key to tropical African species

          Species descriptions

              6. Lactarius indusiatus  Verbeken

              7. Lactarius chamaeleontinus R. Heim

              8. Lactarius madagascariensis Verbeken & Buyck

              9. Lactarius sesemotani  (Beeli) Buyck

              10. Lactarius laevigatus  Verbeken

              11. Lactarius pruinatus Verbeken & Buyck

              12. Lactarius uapacae Verbeken & Stubbe

              13. Lactarius emergens  Verbeken

              14. Lactarius brachystegiae Verbeken & C. Sharp

     Sect. Russulopsidei  Verbeken

          Key to tropical African species

          Species descriptions

              15. Lactarius ruvubuensis Verbeken

              16. Lactarius longipes Verbeken

              17. Lactarius cyanovirescens Verbeken

              18. Lactarius urens Verbeken

              19. Lactarius rufomarginatus  Verbeken & Van Rooij

              20. Lactarius pseudotorminosus R. Heim

              21. Lactarius claricolor R. Heim

              22. Lactarius corbula R. Heim & Gooss.‑Font.

     Sect. Edules Verbeken

          Key to tropical African species

          Species descriptions

              23. Lactarius edulis Verbeken & Buyck

              24. Lactarius nodosicystidiosus Verbeken & Buyck

              25. Lactarius latifolius  Gooss.‑Font. & R. Heim

              26. Lactarius aureifolius  Verbeken

              27. Lactarius densifolius Verbeken & Karhula

              28. Lactarius inversus Gooss.‑Font. & R. Heim

              29. Lactarius phlebophyllus R. Heim

              30. Lactarius roseolus Verbeken

     Sect. Aurantiifolii Verbeken

          Species description

              31. Lactarius aurantiifolius Verbeken

     Sect. Rubroviolascentini (Singer) Verbeken

          Key to tropical African species

          Species descriptions

              32. Lactarius rubroviolascens R. Heim

              33. Lactarius denigricans Verbeken & Karhula

     Sect. Pseudogymnocarpi Verbeken

          Key to tropical African species

          Species descriptions

              34. Lactarius gymnocarpoides Verbeken

              35. Lactarius pseudogymnocarpus Verbeken

              36. Lactarius longisporus Verbeken

              37. Lactarius pumilus Verbeken

              38. Lactarius medusae  Verbeken

              39. Lactarius carmineus Verbeken & Walleyn

              40. Lactarius luteopus Verbeken

     Sect. Rugati Verbeken

          Key to tropical African species

          Species descriptions

              41. Lactarius volemoides Karhula

              42. Lactarius pseudovolemus  R. Heim

              43. Lactarius kivuensis Verbeken

              44. Lactarius rubiginosus Verbeken

              45. Lactarius xerampelinus Karhula & Verbeken

     Sect. Polysphaerophori Singer

          Key to tropical African species

          Species descriptions

              46. Lactarius gymnocarpus R. Heim ex Singer

              47. Lactarius flammans Verbeken

              48. Lactarius albocinctus Verbeken

              49. Lactarius tanzanicus Karhula & Verbeken

              50. Lactarius goossensiae Beeli

              51. Lactarius foetens Verbeken & Van Rooij

              52. Lactarius brunnescens Verbeken

     Sect. Phlebonemi R. Heim ex Verbeken

          Key to tropical African species

          Species descriptions

              53. Lactarius phlebonemus R. Heim & Gooss.‑Font.

              54. Lactarius angustus  R. Heim & Gooss.‑Font.

              55. Lactarius arsenei  R. Heim

              56. Lactarius pisciodorus R. Heim

              57. Lactarius nonpiscis Verbeken

     Sect. Chromospermi Verbeken

          Species description

              58. Lactarius chromospermus Pegler

     Sect. Piperites (Fr. ex J. Kickx f.) Burl. s.l.

          Key to tropical African species

          Species descriptions

              59. Lactarius barbatus  Verbeken

              60. Lactarius acrissimus  Verbeken & Van Rooij

              61. Lactarius afroscrobiculatus  Verbeken & Van Rooij

     Sect. Amari Verbeken

          Key to tropical African species

          Species descriptions

              62. Lactarius subamarus Verbeken

              63. Lactarius amarus  R. Heim

     Sect. Russularia Fr. ex Burl.

          Species description

              64. Lactarius hepaticus Plowr.

     Sect. Nigrescentes Verbeken

          Key to tropical African species

          Species descriptions

              65. Lactarius melanogalus R. Heim ex R. Heim

              66. Lactarius baliophaeus Pegler

              67. Lactarius orientalis (Verbeken) Verbeken

              68. Lactarius griseogalus  R. Heim

     Sect. Plinthogali (Burl.) Singer s.l.

          Key to tropical African species

          Species descriptions

              69. Lactarius angiocarpus Verbeken & U. Eberh.

              70. Lactarius dolichocaulis  (Pegler) Verbeken & U. Eberh.

              71. Lactarius pulchrispermus Verbeken

              72. Lactarius miniatescens Verbeken & Van Rooij

              73. Lactarius sulcatulus Verbeken

              74. Lactarius adhaerens  R. Heim

              75. Lactarius desideratus Verbeken & Stubbe

              76. Lactarius kalospermus (Beeli) Verbeken & Walleyn

              77. Lactarius congolensis Beeli

              78. Lactarius melanodermus R. Heim & Gooss.‑Font.

              79. Lactarius nudus R. Heim

              80. Lactarius rumongensis Verbeken

              81. Lactarius sulcatus Verbeken & Walleyn

              82. Lactarius saponaceus Verbeken

              83. Lactarius pusillisporus Verbeken

              84. Lactarius kabansus Pegler & Piearce

              85. Lactarius sciaphilus Verbeken & C. Sharp

              86. Lactarius tenellus Verbeken & Walleyn

              87. Lactarius acutus R. Heim

              88. Lactarius pseudolignyotus R. Heim

     Sect. Pseudofuliginosi Verbeken

          Key to tropical African species

          Species descriptions

             89. Lactarius atro-olivinus  Verbeken & Walleyn

              90. Lactarius undulatus Verbeken

                 90.1  Lactarius undulatus var. undulatus

                 90.2 Lactarius undulatus var. rasilis Verbeken

     Unclassified taxa

              91. Lactarius badius Verbeken

              92. Lactarius caperatus R. Heim & Gooss.‑Font.

              93. Lactarius hispidulus R. Heim

              94. Lactarius russuliformis (Beeli) Verbeken

     Insufficiently known taxa

              1. Lactarius fulgens R. Heim

              2. Lactarius fulgens var. africanus R. Heim

              3. Lactarius striatus R. Heim

      Excluded taxa

           1. Lactarius lignyotus ss. Dade

           2. Lactarius pellucidus Gooss.‑Font. & R. Heim

3. Lactarius piperatus  ss. Pegler & Piearce and Piearce

4. Lactarius trivialis ss. To & Ob

5. Lactarius uvidus ss. Bresadola. & Saccardo and De Wildeman & Durand

6. Lactarius vellereus ss. Morris & Williamson

7. Lactarius velutinus Bres.

8. Lentinus clitocyboides Henn.

Translation of the keys into French

References

Taxonomic index 

     

Introduction

 

In this book 96 Lactarius species of tropical Africa, including Madagascar, are described, as well as 2 accepted varieties. Except for Lactarius hepaticus, an introduced species which is only found in exotic Pinus plantations, all taxa in the region are endemic for the area.

A recently published molecular phylogeny of the Russulaceae (Buyck & al. 2008) leads to the conclusion that the genus Lactarius as currently defined is not monophyletic and falls apart in two different genera, while one American species, Lactarius furcatus, is transferred together with the Russula species previously assigned to R. subsection Ochricompactae Bills & O.K. Mill. in the seperate new genus Multifurca Buyck & Hofstetter. As the nomenclatural consequences of these results are still pending, the genus Lactarius is presented here in a more traditional concept. However, the sequestrate lactarioid genera Arcangeliella Cavara, Zelleromyces Singer & A.H. Sm. and Gastrolactarius J.M. Vidal are considered synonyms of Lactarius as been shown by molecular research (Nuytinck & al. 2003, Eberhardt & Verbeken 2004, Lebel & Tonkin 2007).

 

Material and Methods

 

The results of this monograph are based on studies of the author’s collections from Burundi, Cameroon, Malawi and Zimbabwe and herbarium specimens from BR, E, FH, GENT, H, K, LG, LY, PC (including an important number of collections previously cited as ‘herbarium B. Buyck’), WAG and material sent by D. Arora, A. Bâ, C. Sharp and D. Thoen. In total about 1400 collections were studied, about 1220 were identified and cited in this monograph. Nearly all literature records of Lactarius have been checked when documented with voucher material, except for the species cited by Onguene (2000) which are therefore not considered in this book.

In the macroscopical descriptions the colours are described according to Kornerup & Wanscher (1978).

Microscopic features were studied from dried material, mainly in Congo-red in L4 (Clémençon 1972), sometimes in NH4OH. Old or bad material was eventually pretreated in KOH 10% solution. Spore ornamentation is described and illustrated as observed in Melzer's reagent. Line-drawings were made using a drawing tube at original magnifications 6700× or 6000× for spores, 3200× or 3000× for individual elements and 1100× or 1000× for sections and surface views. Stippling indicates refractive content in cystidia and lactifers or intracellular pigmentation in the elements of pilei- and stipitipellis. Basidia length excludes sterigmata length. Spores were measured in side view in Melzer's reagent, excluding the height of the ornamentation (Fig. 1f, g).

Measurements are given as (MINa)[AVa-2*SD]–AVa–AVb–[AVb+2*SD](MAXb), with AVa = lowest mean value for the measured collections, AVb = greatest mean value and SD = standard deviation. Q corresponds with spore length/width ratio and is given as (MINQa)Qa–Qb(MAXQb) with Qa and Qb being the lowest, respectively the highest, mean ratio for the measured collections.

The nomenclature of infrageneric taxa follows Redeuilh & al. (2001).

 

Characters used for the identification of Lactarius species

 

1  Macroscopical characters

 

1.1  Basidiocarps

The vast majority of African Lactarius species are agaricoid with a distinct stipe and pileus and a hymenophore consisting of well developed lamellae. Size and consistency are very variable: species with large and firm basidiocarps occur, as well as tiny and brittle species. Besides the agaricoid type, a few sequestrate Lactarii also are known in tropical Africa: a distinctly gasteroid species, Lactarius angiocarpus, and one epigeous species with a distinct pileus and stipe but with a sinuate and glebulose, somewhat radiating to alveolate labyrinthuloid hymenophore.

Most agaricoid Lactarius species have a gymnocarpic development, but some species of L. subgenus Lactariopsis have a partial veil covering the young hymenium. This velum is called a secondary velum by Reijnders (1963) as it originates after the development of the hymenium started and in fact is a fusion of the parallel covering layers of the stipe and the pileus (mixangiocarpic development; Heim 1937, 1938b, Reijnders 1963).

The basidiocarps are characterized by the exudation of latex, in some specimens very scarce or presumably absent, in others extremely abundant.

 

1.2  Pileus

Shape. Most species have a planoconvex to infundibuliform pileus, the shape varies strongly with the developmental phase. In contrast with temperate Lactarii, few umbonate species occur. A papilla is sometimes present (Lactarius griseogalus). In most species, the margin is first incurved, later straight or deflexed. Some species have a conspicuously crenate or crenulate margin (Lactarius undulatus, L. sulcatus).

Size. The diameter of the pileus may vary from 1 (or less, e.g. Lactarius roseolus and L. desideratus) to 15 cm (L. edulis, L. brunnescens, L. latifolius). In general, rain forest species are usually smaller and more brittle than species growing in woodlands.

Colour. There is a large variation in colours, but the main colours can be described as rather dull, especially when compared to many members of the genus Russula: brown, orange-brown, reddish brown, dark brown to greyish or buff. The colour of the pileus is an impor­tant character at species level, and sometimes it might also give some indications on sectional or subgeneric level. However, one has to keep in mind that colours are liable to changes, depen­ding on the age of the basidiocarps and the weat­her conditions. The typical golden yellow to orange pileus margin in young basidiomes of Lactarius edulis disappears soon as the basidiocarp matu­res. Some species have peculiar additio­nal tinges in dried condition; e.g. L. edulis, which shows no red colours in the field, becomes reddish in exsiccatum. Hygropha­neous species are less common in the tropics than in temperate regions, but do occur (e.g. Lactarius rumongens­is).

Surface. The surface aspect of the pileus is often related to the microsco­pic structure of the pileipellis and, therefore, has to be considered as an important taxonomic character. Some common types of surface aspects in temperate species, such as a zonate pileus or a hairy cap margin, are very rare or almost lacking in tropical African spe­cies. Only Lactarius aurantiifolius and L. subamarus have a zonate cap, and only L. barbatus has a hairy cap margin. Another character common for temperate species and lacking in the studied area is a glutinous or slimy pileus. Species with a viscid cap are Lactarius barbatus, L. brachystegiae while L. chromospermus is greasy when humid only.

Rugose, rimulose and finely or even strongly wrinkled pileus surfaces are very common in tropical African Lactarius-species. They occur especially in Lactarius subg. Lactifluus, but also in L. subg. Plinthogalus, where the pileus is usually more velvety. In some species there are even remarkable veins which inspired Heim to define a separate subgenus Venolactarius. Another common type is a dry pileus which becomes cracked and areolate when the basidiomes grow older (especially found in L. section Edules). Dry and finely velvety, slightly pruinose pilei seem to be the rule, while smooth and gla­brous, rather shiny pilei occur spo­radi­cal­ly. A peculiar type is observed in Lactarius section Lactariopsis where a secondary velum occurs. In some representatives this veil is remarkably thick and felty. Stellate rupturing towards the margin shows a smooth and glabrous layer, which is striate or translucently striate at the margin.

Strongly pruinose pilei are present in Lactarius aurantiifolius (whitish pruinose) and in L. medu­sae (velutinate aspect reminding the temperate species L. velle­reus).

 

1.3  Lamellae

Attachment. Attachment of the lamellae is taxonomically not important, as in almost every species the lamellae are adnate to subdecurrent, sometimes beco­ming decurrent when the basidiocarp is older.

Colour. The colour of the lamellae varies mostly from whi­te, whitish, cream-colour to pale yellowish. Some African species have however exceptionally bright coloured lamel­lae: bright yellow to greenish yellow in Lactarius luteopus, dark yellow to golden yellow in L. aureifolius, bright orange in L. aurantiifolius. Lactarius pulchrispermus has pale brown lamellae. The colour of the mature lamellae of Lactarius chromosper­mus exceeds the traditional limits of the genus significantly: they are chocolate-brown by the dark-coloured spores which makes the basidiocarps almost appear like an Agaricus species.

Lamellar edge. The lamellar edge is mostly entire and concolorous, but dark grey or brown in some species of Lactarius sect. Plinthogali (conspicuous in L. saponaceus), white and fimbriate in L. aurantiifolius. Lactarius medusae has a remarkable yellowish orange lamellar edge. The colour of the lamellar edge is a good help to recognize some species but should be considered with care as it seems not constant in all species.

Spacing and branching. The density of lamellae varies from very crowded to very distant. It is an important character on species-level (e.g. Lactarius densifolius vs. L. latifolius in L. sect. Edules) and someti­mes on sectional level (e.g. dense lamellae in L. section Phlebonemi, distant lamellae in L. section Polysphaerophori). Branching of the lamellae occurs often near to the apex of the stipe and this kind of irregular branching is not taxonomically important. Frequently branching lamellae are observed in Lactarius phlebophyllus. Anastomo­sing lamellae or venation between the lamellae may be important on spe­cies level. Lamellulae are present in all spe­cies. They often occur in a regular pattern: often three lamellulae between two lamellae, the middle lamellula being the longest one.

 

1.4  Stipe

Attachment. In some species, such as Lactarius pulchrisper­mus, the stipe is often eccentric, but in most species the stipe is regular and centrally inserted. No representatives of L. section Panuoidei Singer, which have a lateral or no stipe, are known in tropical Africa. 

Shape. The shape of the stipe is mostly cylindrical, someti­mes slightly clavate or tapering downwards. The shape does not seem taxonomically impor­tant, and not even a stable species character; however there are some species with a remarkably long stipe (Lactarius longi­pes), a very short and thick stipe (L. edulis) or an almost pointed stipe which tapers downwards (L. auran­tiifolius).

Colour and surface. The stipe is in most cases concolo­rous with the pileus or slightly paler; an exception is Lactarius luteopus with a vividly yellow to greenish yellow stipe. The surface of the stipe is comparable to the pileus-surface: glabrous, polished, felty or sometimes with veins. Gluti­nous stipes are lacking in the African tropics; fibril­lose or squamulose stipes are rare. At the base of the stipe a subiculum, which is mostly tomentose and paler than the stipe, may be observed. A scrobiculate stipe is only present in Lactarius afroscrobiculatus.

Annulus. In Lactarius sect. Lactariopsis, species with an annulus occur. The annulus is membranace­ous, thin, whitish and not mobile. L. indusiatus has a very fugitive annulus. Annulate species are only known from Central and South America and Africa.

 

1.5  Context

Colour and colour-changes. The colour of the context varies from whitish to cream-colour or pale yellow. Just beneath the pellis the context may have the same colour (or slightly paler) as the pellis, but this colour has no taxonomic importance. A colour-change of the context is often related to the colour or colour-change of the latex (see further). Some remarkable and unique colour and colour changes occur: blackening context in Lactarius section Nigrescentes or context changing to red, violet or black in L. sect. Rubroviolascentini. Species with a slightly pinkening or reddening context occur, as well as species with a strongly browning context.

Consistency. In many species the consistency is firm and solid, but not elastic, rather crumbling. The context in the stipe is solid, fistulous or hollow. A regular chambered stipe, as known in numerous Russula species, occurs in Lactarius aurantiifo­lius.

Smell and taste. Smell and taste are less constant characters than in temperate regions. Distinct smells as Pentamogium bugs, spices, Pelargo­nium, apple, coconut ... are up to now not found in the African tropics. There are some species with a distinct smell of fish (Lactarius pisciodorus, L. nonpiscis), but the range of smells is limited to fish-like, sperm-like or sweetish and fruity. The same is true for the taste of context and latex. In the genus it is very important to distinguish between the taste of the latex and the taste of the context, where this is not given attention, data on the taste of the context are ambiguous. Numerous species described by Heim (1955a) are based on collections from Mme Goossens-Fontana. The data on the taste have to be considered with great suspicion. The use of quinine probably influenced her taste capacity and therefore, a lot of species are described to be acrid or very acrid when they are possibly just mild (Heinemann, pers. comm.). I observed in the field that the taste in some African Lactarius species differs considerably from specimen to specimen (L. sapona­ceus may taste acrid, astringent or soap-like). Other species, like Lactarius urens and L. aureifolius were always burning acrid and their acridity exceeds everything tasted in other continents.

 

1.6  Latex

Presence and abundance. The major macroscopic character which distinguishes Lactarius from Russula is the presence of latex. Fresh Lactarius basidio­mes, under normal conditions, exude latex when the basidiocarp is broken or bruised. In the tropics, the latex is often scarce or even lacking in certain speci­mens, because of dry conditions or an older state of the basidiome (a phenomenon also known from temperate regions). As several species are known from very few collections, it is possible that for some species the latex has not yet been observed. The occasional virtual absence of latex, together with other aberrant macroscopic characters (presence of an annulus, lignicolous habit) may confuse the identification of this genus in the field.

Colour and colour change. Colour and colour change of the latex are characters traditionally used to classify the species within the genus. Nowadays, it is accep­ted that a classification based on such characters is very artificial, but still it remains an important taxonomic character.

Usually, the latex is originally white or watery, remaining so or changing colour. Some species have latex which is coloured from the beginning; bright orange, red, green or yellow latex is not observed in tropical African species. White latex, changing to yellow, is common in European and North American species but not known in tropical Africa. The latex of Lactarius undulatus var. rasilis dries greyish to yellowish, but never turns bright yellow. The most important colour change occurs in species such as L. baliophaeus and L. orientalis; the latex is watery and translucid, becoming bright red and finally greyish or whey-like. In other species of this section the latex turns from whey-like to greyish and black. In Lactarius rubroviolascens, the latex is transparent or pale reddish grey and changes to reddish and black. In several species of Lactarius section Phlebo­nemi the latex is brownish and stains the context brown. The colour of the context may change under influence of the latex; this may also happen when apparently unchanging latex dries up on the context: in L. cyanovires­cens the dried latex and the surroun­ding context become bluish green.

In some temperate species a colour change of the latex is observed when bringing the latex on a white tissue or paper. I tried this out several times during my fieldwork in Africa, but only observed a reaction in L. desideratus, recently described from Cameroon. In this species the milk turns distinctly yellow on white tissue. When observing latex colours it is important to observe the fresh mushroom over some hours.

Taste. Often latex is scarce, and its taste difficult to observe separately from the context. In Lactarius urens and L. aureifolius however, the latex is so abundant that it is easy to observe that the latex is as hot and burning as the context. The latex of these species is even so acrid that it causes a burning and irritating feeling in contact with the skin, which lasts for hours.

 

2  Microscopical characters

 

2.1  Basidiospores

Spore deposit. Spore deposit colours in Lactarius vary from white to dark buff, but the African L. chromospermus outlines these limits by far with its dark chocolate brown spore deposit (which becomes paler brown after drying). Apart from L. chromospermus, the darkest spore print in tropical African species is observed in L. pulchrispermus. Obtaining spore prints in the tropics appears not easy (basidiocarps rotten quickly etc.) and data are far from complete. Spore deposit colours noted by Mme Goossens-Fontana should be interpreted with care since she usually took a piece of a lamella and rubbed it on a white paper, thus obtaining the so-called spore colour. When she took a real spore deposit, she imita­ted the colour by a water-colour and threw the spore deposit back into nature (Heinemann, pers. comm.).

Size and shape. The spores are bilaterally symmetric along the longitudinal axis, the adaxial side is applanate or slightly convex, sometimes even slightly depressed, while the abaxial side is strongly convex. Only length (distance of the longest axis) and width (distance of the shortest axis when observed in profile) are measured. The spore ornamentation is not included in these dimensions (Fig. 1f, g & h).

The overall shape of the spores is determined by the length:width ratio, the quotient (Q). Globose spores are defined as having Q ranging from 1.00 to 1.05, subglobose as Q = 1.06 to 1.12, ellipsoid 1.13 to 1.39 and elongate spores have a Q bigger than 1.40, this according to Buyck (1991) but without making the distinction between broadly and clearly ellipsoid spores.

The size and the shape of the spores are remarkably constant throug­hout Russulaceae. The range according to Hesler & Smith (1979) is 512 × 59 mm, with very few species having spores outside this range. Among the African taxa, the longest spores are found in Lactarius carmineus (1113.5 × 810 µm) and L. longis­porus (8.512.5 mm), the shor­test ones in L. pusillisporus (5.37.1 mm) and L. fulgens var. fulgens (4.75.8 µm, but material in very bad condition). The broadest spores are these from Lactarius sub­amarus (7.79.3 mm) and the narrowest ones from L. badius (width 4.05.6 mm) and L. fulgens var. fulgens (3.85 µm, but material in very bad condition). No strictly bisporic species are known in tropical Africa.

The spore shape varies from subglobose to ellipsoid, rarely elongate. In the African taxa, the average Q varies from 1.031.05 (globose) in L. pulchrispermus to 1.6 and even more (elongate) in L. longispo­rus. Most species have a Q value around 1.15 to 1.30 (ellipsoid). 

Ornamentation. The amyloid spore ornamentation is a typical feature for the Russulales and a very important character in the delimitation of species and often also characteristic for higher taxonomical levels. The patterns of the amyloid ornamentation range from isolated low warts to a completely winged and heavy reticulum. Descri­bing the highly differentia­ted spore ornamentation in the diffe­rent species has never been easy. Josserand (1941) stated that "the ornamenta­ti­on of the diffe­rent species shows such a variety of decorative combinations that one may wonder if it is not the inflexibility of a wrong mind wanting to define them rigorously. It's like demarca­ting a moving thing." Romag­ne­si (1967) agrees that words are insuffi­cient to describe an ornamen­tati­on.

Given the difficulties in giving an accurate and unambiguous descripti­on of the spore-ornamenta­tion, drawings of Russulaceae spores are indispensable. The use of Scanning Electron Microscopy contributes to the study of the spore ornamen­tation ["the additional magnificati­on and resolution possible with the SEM leaves no doubt about the characters of the spore surface previously suggested by the light microscope" (Homola & Kimball, 1975)], without derogation to the value of dra­wings made by light microscope, which are more practical when it comes to identifications and observation of the amyloidity. To describe this complex character following characters are used:

• Maximal height of spore ornamentation only the maximal height is taken into account as there are always lower ornamentations in between the higher ones. The lowest ornamentation in the African taxa is found in species like Lactarius rubroviolas­cens (unmeasura­ble with a light microscope, lower than 0.1 mm), the highest in L. nudus (up to 3 mm).

• Shape of the spore ornamentation in the case of isolated ornamenta­tion units it is easy to determine whether they are acute and sharp or rounded, rather truncate or cylindrical or even hemispherical. When the ornamentation is composed of ridges, the shape is usually considered as sharp, but in some species the ridges have distinctly rounded edges.

• Type of the spore ornamentation this considers the shape of the basis of the most important units of the ornamentation; these may be linear, irregular or rounded (or in case of almost smooth spores: not recognizable).

• Connections of the spore ornamentation the connections may be crest-like, meaning that they are as high as the basic units, and as a result the basic units are mostly not recognizable any more. The connections may be of a lower height and are then observed as fine lines connecting the basic units. The connections may be lacking, then the basic units are isolated.

• Reticulation of the spore ornamentation the overall view of the ornamenation can be described as completely reticulate, partly reticulate or not at all reticula­te. Besides this we also distinguish zebroid spores.

In some species, aberrantly ornamented spores are observed. These spores may have the same size as normal spores, but the ornamenta­tion is aggregated into droplet-like, globose warts, which are irregular in size and number. Some of these warts may even become loosened from the spores and float free in the mount as amyloid globules, which was also observed by Hesler & Smith (1979). Heim (1955a: fig. 3.15) illustrated such a spore for Lactarius melanogalus. I observed them in numerous African (e.g. Lactarius melanoga­lus, L. corbula) and several European and Asian species. The phenomenon occurs occasio­nally and does not seem to be associated with any species in particu­lar. Malençon (1931) used these abnormal spores to support his hypothesis about the destructive origin of the spore ornamenta­tion (e.g. Malençon, 1931: Pl. 4, fig. 3.6).

Plage. At the adaxial side, above the hilar appendix or apiculus, there is a differentiated zone called the suprahilar plage, where the normal ornamentation is usually absent or very reduced. The amyloid reaction of this plage is an important taxonomical feature. The plage can be non-amyloid (naked or almost naked, Fig. 1a), centrally amyloid (with a small amyloid or faintly amyloid spot in the centre, this type often occurs in lowly ornamented spores, Fig. 1b), distally amyloid (only amyloid in the part closest to the ornamentation, often occurring in highly ornamented spores, Fig. 1c, 1d) and totally amyloid (plage is completely amyloid, a very common type in Russula but rare in Lactarius, Fig. 1e).

 

2.2  Basidia

Though as in most Agaricales s.l., the size and the shape of the basidia are no important taxonomical features, there seems to be a relation between the volume of the spores and the volume of the basidia. In the large-spored species (Lactarius barba­tus, L. undulatus var. undulatus), long and broad basidia occur. The smallest basidia among the African species (3045 mm) are found in L. pusillispo­rus and L. badius, both species with remarkably small spores (Fig. 2). There could also be a relation between the ornamentati­on-type of the spore and the basidium type. Very long and slender basidia often produce lowly ornamented spores, while most of the strongly winged or zebroid spores of several members of L. sect. Plinthogali are formed by broad and almost clavate basidia with rather slender sterigmata.

The length of the basidia is measured without sterigmata and the width is measured at the largest place. Accor­ding to Hesler & Smith (1979), the basidia in Lactarius should be at most 60 mm long and 14 mm wide. In the African species however, there are several species with basidia up to 80 mm long. The measure­ments are indicated as a certain range with extreme values in be­tween brackets, no average values are given. The basidia are obser­ved in the middle part of the lamellae, not very close to the margin (where they are significantly smaller). The longest basidia are found in Lactarius edulis (6080 mm), the broadest in L. undulatus var. undulatus (1114 mm), the shortest in L. badius (3240 mm) and the narro­west in L. aureifolius and L. badius (68 mm).

As a rule, basidia of agaricoid Lactarius species have four sterigmata. Up to now, only the European L. acerri­mus is known to have exclusively 2-spored basidia. Two-spored basidia are sometimes observed in other species but the percentage of these 2-spored basidia is usually very small. I observed 2-spored basidia in Lactarius inversus (abun­dant), L. longipes, L. acutus, L. adhaerens, L. annulatoan­gus­tifolius and some other species (Fig. 3a, 3b). In Lactarius inversus also 1-spored basidia are present (Fig. 3c), and occasionally even 5-spored basidia were observed (L. luteo­pus and L. kabansus, Fig. 3d, 3e). Sequestrate taxa are often 2-spored, but both African species are 4-spored. 

The sterigmata may be curved or straight, but this character varies from basidium to basidium and is not constant for a species, not even for a basidiome. Especially in 2-spored basidia, the sterigmata may be deformed and extremely long (though they still produce a spore). Sometimes deformed basidia resemble deformed pleuromacro­cystidia, which could be interpreted as transi­tional stages. This is especially observed in Lactarius chro­mosper­mus (Fig. 3f). The longest sterigmata are found in Lactarius urens (810 mm).

 

2.3  Pseudocystidia

Pseudocystidia are extremities of laticiferous or diffe­rentiated hyphae, ascending in the hymenium where they may be emergent or not. In Lactarius basidiocarps they are always present, though sometimes very scarce or hard to observe, and form in fact the best distinction with the genus Russula, where they are always absent.

The content is comparable with the content of the hyphae of the laticiferous system: refringent, dense, oleiferic or needle-like to granular, yellowish in water or KOH, greyish in sulfovanillin.

The shape varies from cylindrical to fusi­form and more spectacular shapes (such as corkscrew-like or branching) occur more commonly in African species than in species of other continents; the top is rounded or tapering and sometimes even for­ked. The presence of these pseudocystidia is a generic charac­ter and thus not taxonomically important within the genus, but the shape, the size and the emergence are important characters at infrageneric level. They may occur both on the face (pleuropseudocystidia) (Fig. 4) and on the edge (cheilopseudocystidia) (Fig. 5) of the lamellae. Extremely emergent and broad pleuropseudocystidia occur in L. subg. Lactariopsis. The broadest pseudocystidia are observed in Lactarius pelliculatus and L. zenkeri.

 

2.4  True cystidia

True cystidia sometimes have the same content as the laticiferous system (then called macrocysti­dia) but they are never connec­ted with a lactifer, so a delimitating septum is always present. The presence, abundance, type and size are important characters to recogni­ze a species. One third of the African taxa has true cystidia, belonging to the following types:

Lamprocystidia are cystidia with thickened walls (Fig. 6a, 6b). They are usually emergent, cylindrical and rounded on top. They originate in the subhymenium (exceptionally in the trama, as in the temperate species Lactarius volemus). Emergent lamprocystidia are typical for L. subg. Lactif­luus. The largest cystidia belong to this type: 110140 ´ 1015 mm in Lactarius rubroviolas­cens and 80130 ´ 812 mm in L. gymnocarpoi­des. Because of their large size, lamprocystidia may sometimes be observed with a handlens, also in the dried material. Some species (Lactarius aurantiifolius, L. baliophaeus, L. melanoga­lus) have slightly thick-walled cystidia, embedded in the hymenium, with the same shape as the basidioles.

Macrocystidia with a needle-like content (Fig. 7), slightly grey­ish in sulfovanillin, occur in Lactarius pulchrispermus, L. nudus and L. chromospermus. They are fusiform and tape­ring or moniliform on top. In Lactarius chromospermus and L. pulchrisper­mus the cystidia have slightly thickened walls and could be called lampromacrocystidia. These cystidia are sometimes septate. The typical capitate, thin-walled macrocystidia which are so common in Russula and in temperate Lactari­us species do not occur in tropical African Lactarius species. Rounded, cylindrical macrocysti­dia with slightly thickened walls occur in L. urens. I also use the term macrocysti­dia for these cystidia which have exactly the same size and shape as the pseudocystidia in the same species, but without granular, oleiferic or needle-like content (observations on the content are here based on dried material). These cystidia often arise very deep in the subhyme­ni­um or in the trama. They are present in Lactarius badius, L. densi­folius and L. ruvubuensis.

Leptocystidia are thin-walled cystidia without remarka­ble content (Fig. 6c, 6d, 6e) and thus only deviating by their shape. They are tapering at the top and often even have a rostrate apex, which makes them easy to confuse with monosterig­matic basidia. One can consider them to be cystidia if they are regularly observed and if they never bear a spore or spore primordi­um. They occur in Lactarius indusiatus and L. acutus.

 

2.5  Marginal cells

Pseudocystidia or true cystidia may occur at the edge of a lamella and are then called cheilopseudo­cystidia and true cheilocystidia; they resemble the pleurocystidia present in a same species, but are usually smaller. Their presence on the lamellar edge does not implicate that the edge is sterile, on the contrary, it usually means that the hymenium, as it occurs at the lamella-sides, prolongs at the edge and thus contains cystidia among basidioles and basidia. However, in numerous Lactarius species the edge is sterile and consists of sterile elements which occupy the entire edge. These elements differ from the pleurocystidia and are in fact "hairs" sensu Romagnesi. They are called marginal cells here. They are mostly thin-walled and hyaline, but may also contain a remarkable dark content (in species with a dark lamellar edge, e.g. L. congolensis). The shape varies from clavate, fusiform to irregular. The cheilocystidia are sometimes branching or septate. In a few cases they are long, cylindrical and narrow. Marginal cells are often comparable (concerning shape, thickness of the wall and pigmentation) to the elements of the stipiti- or pileipellis occurring in the same species (e.g. L. aurantiifolius, L. sapona­ceus) (Fig. 8).

 

2.6  Hymenophoral trama

The hymenophoral trama is bordered by the usually well developed subhymenium, mainly composed of subisodiametric cells. Lacti­fers are especially present in the hymenop­horal trama of Lactarius, but also occur in the lamellae of Russula (Fig. 9f). 

Where Russula is traditionally distinguished from Lactarius by the presence of rosettes (clusters of sphaerocytes) in the hymenophoral trama, this difference seems hardly maintainable. Not only do all Lactarius species contain single globose cells in the trama, but some species also show distinct rosettes. This is true for the European Lactarius volemus, (Fig. 10a, 10b) but also for several African species which have a hymenophoral trama that looks exactly like an average Russula-trama (sections Polysphaerophori, Russul­opsi­dei, Lactariopsidei). On the other hand, Buyck (1989b) discovered that tropical Russulae without sphaero­cytes in the hymenophoral trama exist: in Russula oleifera var. levecqui, the trama of the lamellae is entirely filamentous, without any sphaerocyte, which confirms again that the absence or presence of sphaerocytes in the hymenop­horal trama is not useful as distinction between the two genera.

A hymenophoral trama composed of sphaerocytes is here called cellu­lar (Fig. 11b), a trama composed of hyaline hyphae (with some occasional globose cells) filamentous (Fig. 11a). A mixed hymenophoral trama is observed in some species. The lamellar trama is observed on mature basidiomes and the sections of the lamellae are made halfway the pileus. The structure of the hymenophoral trama is considered to be taxonomical­ly very important and is a constant character in many sections.

 

2.7  Structures of pilei- and stipitipellis

Especially the structure of the pileipellis is a very important phylogenetic character and it is also reflected in the macroscopical aspect of the basidiocarp. By looking at the pileus surface (both macro- and microscopical), one can tell in most cases which subgenus the species belongs to. These macroscopical features of the pileus (viscid, velvety, tomentose, squamulose) were since long used as important characters to delimitate certain groups, but it lasts until 1980 before the microscopic characters of the pileipellis play a major role in the identification key, as well as in the classification system.

It is true that the structure of a pileipellis and stipitipellis may be variable within a species according to the developing stage and according to the place on the basidiome, but the variation is limited; a cutis may become an ixocutis or a trichoderm but not a cellular structure. Another frequently observed phenomenon is that thick-walled ascending elements are much denser when a basidiome is young but may become apparently less frequent when the basidiocarps are older. In this study pilei- and stipitipellis structures are observed on mature, but not too old basidiomes; drawings were made halfway the pileus radius or halfway the stipe height.

The pellis typology and terminology used in this study is explained here. To characterize a pellis-structure four basic characters have to be observed:

Presence of thick-walled elements In tropical species the presence of thick-walled and mostly hair-shaped elements is much more common than in temperate species. Elements are considered to be thick-walled when the walls measure 1 mm or more. The presence of thick-walled elements is reflected in the name of the structure by adding the prefix “lampro”, for example in lamprotrichoderm and lampropali­sade. In most cases the thick-walled elements form an entire upper layer, but there are some particular cases where they only occur scattered in a pileipellis­ structure consisting of thin-walled elements, I call this latter type "mixed"; it is observed in L. sect. Chamaeleontini.

Presence of isodiametric cells A distinct layer of isodiametric cells may be present, isodiametric cells may also occur scattered in the pellis-structu­re or they may be totally absent. The scattered occurrence of isodiametric cells is often due to the inflation of parts of hyphae. A distinct layer of isodiametric cells is mostly basal, but in rare cases the whole pileipellis consists of isodiametric cells.

Orientation of the terminal elements The upper layer of the pellis consists of cylindrical terminal elements, which may also be undifferentiated hyphal endings, these may be arranged periclinic, anticlinic or obliquely in relation to the underlying surface.

Presence of a slime-layer Especially in the case of a cutis or trichoderm the hyphae may secrete slime or the walls become gelatinized which results in a visible slime-layer embedding the upper layer. As in tropical Africa the group with slimy, viscid or glutinous pileus is restricted, the presence of a typical covering slime layer is rare. In the tropical species some other slime-layers can be observed: in Lactarius sulcatulus there is a very thin and well-delimited slime-layer covering the pileipellis which is a hymeniderm. It is not clear how this slime origina­ted and as such a structure is only observed in one species, no special name is given to this type. In another species, L. undulatus, the underlayer has a slimy appearance.

 

The combination of these four characters leads to the following types, between which intermediate forms may of course occur:

Pellis without inflated elements or sphaerocytes, composed entirely of filamentous elements

 

a. cutis: the upper layer consists of mostly hyaline and thin-walled hyphae which are pericline, recumbent and paral­lel or slightly intermixed. Sometimes the only differen­ce with the underlying pileustrama is a more dense and compact structure of the pellis. Differentiated structures are mostly lacking, although pileo­cysti­dia with a special shape or content may occur (Fig. 12a, 14a).

 

b. ixocutis: the hyphae of the cutis may secrete slime or the walls of the hyphae gelatinize, in dried material it is impossible to detect which of the two processes occurred, maybe they even occurred together; this results in a slime layer wherein parallel, very thin and hyaline hyphae are visible (Fig. 12b, 14b).

 

c. trichoderm: the pellis consists of mostly hyaline and thin-walled hyphae, but at least part of them are ascending and then anticline or oblique; in the most typical case all termi­nal elements are anticline and form a dense turf of "hairs" (Fig. 12c, 14c).

 

d. ixotrichoderm: same structure as a trichoderm but the hyp­hae are gelati­nized or secrete slime, which results in being embedded in a slime-layer (Fig. 12d).

 

e. lamprotrichoderm: the ascending, anticline terminal elements are clearly differentiated, mostly by being thick-wal­led (Fig. 12e, 14d).

Pellis with a distinct layer of inflated elements or sphaerocytes

 

f. irregular epithelium: cellular structure, pseudoparenchymatic struc­ture, the upper layer is completely composed of isodiametric cells, which are irregu­larly ordered (Fig. 12f).

 

g. regular epithelium: subcellular structure, pseudoparenchymatic structu­re, the upper layer is completely com­posed of isodiametric (or almost isodiametric) cells, these cells are not irregularly ordered, but more or less arranged in anticline rows (Fig. 12g, 14e).

 

h. palisade: consists of an upperlayer of anticline, elongated, hair-shaped elements and an underlying dense and com­pact layer of isodiametric cells (Fig. 12h, 15a).

 

i. lampropalisade: a palisade with thick-walled terminal ele­ments (Fig. 13a, 15b).

 

j. hymeniderm: special case of palisade where the terminal elements are not elongate and septate (as is often the case in a palisade) but clavate; the underly­ing layer of isodiametric cells is often rather thin, the whole structure remin­ding thus somewhat a hymenium (Fig. 13b, 15c).

Pellis with isodiametric cells or sphaerocytes, but these never forming a distinct layer

 

k. trichopalisade: between a trichoderm and a real palisade; this may look like a trichoderm where parts of the ascen­ding, anticline hyphae are inflated or almost roun­ded; it may also be a structure where some of the terminal elements are ascending from isodiametric cells, others are ascending from hyphae (Fig. 13c, 15d).

 

l. lamprotrichopalisade: a trichopalisade where the terminal elements have thickened walls (Fig. 13d, 15e).

 

Pigmentation Extracellular pigmentation usually needs to be observed on fresh material, this type of incrustrations has only been reported for Lactarius arsenei and L. latifolius (Heim 1938b, 1955a). The intracellular pigmentation is visible over a longer period, even in older exsiccata. Many of the African spe­cies, especially of L. subg. Plinthogalus, have intracellular pigmentation in the pileipellis: the elements of the upper layer have a remarkable brownish content.

Dermatocystidia – Dermatocystidia usually occur in a cutis or ixocutis and are very common in Russula species, but never occurring in temperate Lactarius species. In African Lactarius however, dermatocystidia occur in almost all members of L. sect. Russulopsis and in L. chromospermus (Fig. 9a, 9b, 9c). 

 

Distributional patterns

 

In this study material from 19 different countries is included (Benin, Burundi, Cameroon, Central African Republic, Congo, Gabon, Ghana, Guinée, Ivory Coast, Kenya, Liberia, Madagascar, malawi, Nigeria, Senegal, Tanzania, Togo, Zambia and Zimbabwe) but of course the exploration rate per area is very variable, with some areas which hardly have been prospected. This is illustrated by the fact that about 25% of the actually known species are only known from the type locality. We realize that the real number of Lactarius species is higher and that more new species certainly will be discovered. An overview of the collections sites is given in figure 16.

Though conclusions about the species distribution can only be provisional, we notice that most of the species have been collected either exclusively in woodlands (miombo, Uapaca woodland, Sudanian woodland, …) or in more humid forest types (rainforest, riparian forest, gallery forest, swamp forest, …) suggesting a high ecological selection. Other species occur in various forest types and seem widespread in tropical Africa: L. annulatoangustifolius (Fig. 17), L. chamaeleontinus, L. rubroviolascens

Some species (L. heimii (Fig. 18), L. brunnescens, L. chromospermus, L. urens) are restricted to the Zambezian region (as defined by White, 1983) and others occur in both the Zambezian and Sudanan region (L. longisporus, L. emergens, L. luteopus (Fig. 19)), though the latter is poorer in ectotrophs and lacks important mycorrhizal tree genera as Brachystegia and Julbernardia.

Both the Guineo Congolian region (L. gymnocarpus (Fig. 20), L. russuliformis) and Madagascar (L. madagascariensis (Fig. 21), L. phlebophyllus) might be considered as centre of endemic ectotrophs, but they also have species in common (L. annulatoangustifolius, L. pelliculatus (Fig. 22)).

The existence of e.g. Uapaca gallery forests in the woodland regions makes it possible for Guineo-congolian ectomycorrhizal fungi to invade these regions (L. melanogalus (Fig. 23), L. acutus (Fig. 24)).

 

 

Abbreviations

 

The following abbreviations are used: Q = length/wide ratio of the spores, n = number of spores measured, L = number of entire lamellae, l = number of lamellulae. In the illustrations H stands for the elements of hymenium, H mc for marginal cells, H(p) for hymenium (profile view), H plcy for pleurocystidia, H plpscy for pleuropseudocystidia, P pe for the elements of pileipellis, P pe (p) for pileipellis (profile view), P pe (s) for pileipellis (surface view), S pe for the elements of stipitipellis and sp for basidiospores. The scale bar always represents 10 µm.

Numbering of the figures in the plates refers to the numbering of the taxa in the text.

Herbaria acronyms follow Holmgren & Holmgren (1998), colour codes are according to Kornerup & Wanscher (1978), authors of fungal names are abbreviated according to Kirk & Ansell (1992).

 

Lactarius Pers.

 

Lactarius Pers., Tent. Disp. Meth. Fung.: 63 (1797), as “Lactaria,” conserved orthography (Taxon 37: 456, 1988). – Lectotype: Lactarius piperatus (L.: Fr.) Pers. (Earle 1909: 409).

Agaricus section Lactifluus Pers., Syn. meth. fung.: 429 (1801); Lactifluus (Pers.) Roussel, Fl. Calvados, 2ème éd.: 66 (1806), lectotype: Lactifluus piperatus (L.: Fr.) Kuntze (Earle 1909: 409); Agaricus tribus Galorrheus Fr.: Fr., Syst. mycol. 1: 61 (1821); Galorrheus (Fr.: Fr.) Fr., Stirpes Agri Femsion. 3: 56 (1825), lectotype: Galorrheus piperatus (L.: Fr.) Fr. (Donk 1949); Lactariella Schröter in Cohn, Kryptog.-Fl. Schlesien, Pilze 3(1): 544 (1889), lectotype: Lactariella lignyota (Fr.) Schröter  (Singer & Smith 1946); Arcangeliella Cavara, Nuovo Giorn. Bot. Ital., ser. 2, 7(2): 126 (1900), type: Arcangeliella borziana Cavara; Lactariopsis Henn., Bot. Jahrb. Syst. 30: 51 “1901” (1902), type: Lactariopsis zenkeri Henn.; Gloeocybe Earle, Bull. New York Bot. Gard. 5: 409 (1909), type: Gloeocybe insulsa (Fr.: Fr.) Earle; Pleurogala Redhead & Norvell, Mycotaxon 48: 377 (1993), type: Pleurogala panuoides (Singer) Redhead & Norvell; Zelleromyces Singer & A.H. Sm., Mem. Torrey Bot. Club 21(3): 18 (1960), type: Zelleromyces cinnabarinus Singer & A.H. Sm.; Gastrolactarius R. Heim ex J.M. Vidal, Rev. Catalana Micol. 46: 76 ‘2004’ (2005), type: Gastrolactarius densus (R. Heim) J.M. Vidal.

 

brief history of Lactarius collections from Tropical Africa

 

Before our studies the knowledge of the genus Lactarius Pers. in tropical Africa was almost completely based on the monographs of Heim for Madagascar (1938b) and Congo and former French colonies in Western Africa (Heim 1955a, 1955b). Before Heim some other authors described several species receiving little attention until recently (Verbeken 1996a). Eichelbaum (1906) and Walker (1931) mentioned some vernacular names of Lactarius-like fungi without giving full descriptions, whereas Bresadola (in De Wildeman 1914) described a new species, Lactarius velutinus, which turned out to be a Russula (Buyck 1988). Beeli (1928) also described two Lactarius species and Hennings (1902) created Lactariopsis in which he described the annulate Lactariopsis zenkeri, later placed in Lactarius by Singer (1942). The presence in the tropics of veiled Lactarius species, species fructifying on rotten wood and species with a very restricted presence of milk, together with his lack of field experience in the tropics, apparently confused Beeli (1927a, 1927b, 1928, 1933, 1936) as he described Lactarius specimens in the genera Armillaria (1), Omphalia (1), Clitocybe (1), Russula (2) and Laccaria (1) (Verbeken 1996a).

More recently, scattered descriptions of African Lactarius species, including some new species can be found in Berthet & Boidin (1966), Heim (1966, 1967), Morris (1984, 1987, 1990), Pegler (1969, 1977, 1982) and Pegler & Piearce (1980). Our studies of tropical African milkcaps started in 1993, initially based on the collections of BR (mainly collected by M. Goossens-Fontana, M.C. Schmitz-Levecq, J. Rammeloo, D. Thoen, B. Buyck, J. Schreurs), Bart Buyck (from Zambia and Burundi, now at PC), Härkönen and coll. (Tanzania, H), and personal collecting in Burundi (preserved at BR). More recently, collections have been studied of André de Kesel (Benin, preserved at BR), Bart Buyck (Madagascar, preserved at PC), Roy Watling and Peter Roberts (Cameroon, E & K), Jérôme Degreef (Gabon, BR), A. Verbeken & F. Noe (Malawi, GENT), A. Verbeken & C. Sharp (Zimbabwe, GENT). African milkcaps received also attention in several modern studies on edible fungi from Burundi (Buyck 1994), Tanzania (Härkönen & al. 1995, 2003) and Benin (De Kesel & al. 2002, Yorou & De Kesel 2002, Yorou & al. 2002). The number of accepted species has raised from 35 in 1989 to 96 in 2008 (Buyck & Verbeken 1995; Buyck & al. 2007; Eberhardt & Verbeken (2004); Karhula & al. 1998; Van Rooij & al. 2003; Verbeken 1995a, 1995b, 1996a, 1996b, 1996c, 1996d, 1998a, 1998b, 2001a; Verbeken & Sharp 2003; Verbeken & Walleyn 2000; Verbeken & al. 2000, 2008). The real number of tropical African Lactarius species is estimated to be at least 125 (Verbeken & Buyck 2001).


PRACTICAL key to sections of the genus Lactarius in tropical Africa

 

1.    Carpophores sequestrate (gasteroid or secotioid)............................. sect. Plinthogali s.l.

       Carpophores with normally developed stipe and lamellae ..............................  2

 

2.    Species associated with exotic Pinus trees; cap reddish brown........... sect. Russularia

       Species associated with indigenous trees (mainly Caesalpinioideae, Uapaca, Papilionoideae, Dipterocarpaceae) .....  3

 

3.    Stipe with a distinct, more or less fugaceous annulus .......................  sect. Lactariopsis

       Stipe without an annulus; velar remnants only present at pileus margin or absent................... 4

 

4.    Pileus margin with velar remnants ..................................................  sect. Chamaeleontini

       Velar remnants absent .................................................................  5

 

5.    Context blackening ........................................................................  6

       Context not blackening (browning, unchanging etc.) .............................  7

 

6.    Hymenium with lamprocystida; spores ornamented with low warts or ridges ........ sect. Rubroviolascentini

       Hymenium without lamprocystidia; spores with winged ornamentation, at least 1 µm high ..................  sect. Nigrescentes

      

7.    Spore print and mature gills chocolate brown; pileus viscid ......................  sect. Chromospermi

       Spore print white to yellowish or pale pinkish, at most pale brown; pileus dry or viscid ...........  8

 

8.    Pileus viscid with strongly hairy margin OR stipe scrobiculate .........  sect. Piperites s.l.

       Pileus viscid or dry, cap margin not hairy, stipe never scrobiculate ..............................................  9

 

9.    Pileus pruinose, orange and concentrically zonate when moist; lamellar edge fimbriate, appendiculate, with transparent dropplets when fresh; stipe tapering downwards and clearly chambered .................................. sect. Aurantiifolii

       Not with this combination of characters ......................................  10

 

10.  Hymenium with conspicuous lamprocystidia ........................  sect. Pseudogymnocarpi

       Hymenium without lamprocystidia ................................................  11

 

11.  Pileipellis a palisade with an upper layer of anticline, thick-walled elements (lampropalisade); context (e.g. gills) often browning when bruised ..................................................................... 12

       Pileipellis structure different, in case of a palisade without thick-walled elements .................. 13

 

12.  Spore ornamentation typically composed of almost isolated, distinct rounded warts and some very fine connective lines between them .......................................  sect. Phlebonemi

       Spore ornamentation more or less reticulate .............................  sect. Polysphaerophori

      

13.  Spore ornamentation zebroid .....................................................................  sect. Plinthogali

       Spore ornamentation different ................................................... 14

 

14.  Pileus dull coloured (brown, greyish, coffee with milk, buff), without orange or reddish tinges; spores often winged or reticulate, sometimes (sub)globose .................................................  15

       Pileus differently coloured, often more vivid, with orange or reddish tinges ............................  17

 

15.  Spores small, 6–7 × 4–5.5 µm, ellipsoid to elongate; pileipellis a trichoderm .........  L. badius

       Spores larger or subglobose; pileipellis a palisade or trichopalisade .........................................  16

 

16.  Pileipellis a palisade or hymeniderm, dry, often velvety or finely tomentose to slightly squamulose; context sometimes changing pinkish when bruised ............. sect. Plinthogali

    Pileipellis a trichoderm, smooth, sometimes shiny or subviscid; context not changing pinkish when bruised ........ sect. Pseudofuliginosi

      

17.  Carpophores rather small; pileus ochraceous, concentrically zonate when fresh; stipe fistulous; pileipellis a cutis to trichoderm, composed of long interwoven hyphae ........... sect. Amari

       Not with this combination of characters ..................................  18

 

18.  Pileipellis a palisade, with an upper layer of anticline elements; basidia long and slender; spores ellipsoid to elongate, verrucose or more or less reticulate, plage often with a central amyloid spot; pileus dry, orange, yellowish, reddish, reddish brown (sub)globose .......... sect. Rugati

       Pileipellis structure different ..........................  19

 

19.  Pileipellis an ixocutis (to locally ixotrichoderm) and cream-coloured...... sect. Piperites

       Pileipellis dry or viscid but not an ixocutis, if an ixotrichoderm then pileus orange ................  20

 

20.  Pileipellis most often with scattered thick-walled hairs; pileus shiny and smooth, dry to viscid, margin often striate or sulcate; pleuropseudocystidia emergent to very emergent, mostly broad and fusiform ....................  sect. Chamaeleontini 

       Pileipellis dry, lacking thick-walled hairs .........................................................................................  21

 

21.  Pileus < 35 mm diam., ochraceous red, brownish red, tomentose to finely scaly ........ L. hispidulus

       Not with this combination of characters ...........................................................................................  22

 

22.  Basidiomes reminding of a small, reddish or pinkish Russula; spore ornamentation composed of slender spines up to 1.5–2 µm high, regularly connected by fine connective lines .....  L. russuliformis

       Not with this combination of characters ...................................  23

 

23.  Pileus vividly ochraceous orange; lamellae dense; spores with rounded, mostly isolated warts; pleuromacrocystidia abundant, slightly emergent and with dense needle-like content ..............................  L. caperatus

       Not with this combination of characters .................................................................  24

 

24.  Pileipellis dry, a trichoderm or composed of chains of subcylindrical to subsphaerical cells (cap often cracked); pileomacrocystidia absent ...............................................  sect. Edules

       Pileus dry to slightly viscid; pileipellis cutis-like with distinct macrocystidia; pileus often with reddish colours; pseudocystidia often branched and diverticulate ........ sect. Russulopsidei


Sect. Lactariopsis  (Henn.) Singer

 

Lactarius sect. Lactariopsis (Henn.) Singer, Ann. Mycol. 40: 111 (1942) (as Lactariopsideae).

     Lactariopsis Henn., Bot. Jahrb. Syst. 30: 51 “1901” (1902).

     sect. Lactariopsidei “Singer ex Singer”, Sydowia 15: 83 (1962, illegit.).

Type species: Lactarius zenkeri Henn.

 

Key to tropical African species

 

1.  Thick-walled hair-shaped elements in the pileipellis scarce, pleurocystidia present ... sect. Chamaeleontini,  6. L. indusiatus

     Pileipellis entirely composed of thick-walled and hair-shaped elements, pleurocystidia absent ........... 2

 

2.  Spore ornamentation well developed, up to 1 mm high .....................  1. L. annulatoangustifolius

     Spore ornamentation faint, mostly up to 0.2 mm high ........................................................................  3

 

3.  Spores ellipsoid to elongate, Q = (1.15)1.3–1.5(1.65), spores up to 11.5 mm long; spore-ornamentation an almost complete reticulum ................  4. L. heimii

    Spores ellipsoid, sometimes subglobose, Q = (1.09)1.19–1.32(1.45), spores usually shorter than 9(10) mm; spore-ornamentation an incomplete reticulum, always with distinct warts ............. 4

 

4.  Pileipellis remarkably thick, felty, yellowish white, persistent, stellately rupturing; spores 8.4–9.2 mm long; only known from Zambezian miombo woodland ..........................  5. L. velutissimus

     Pileipellis thinner, submembranaceous ..........................................  5

 

5.  Basidiomes fragile, yellowish brown to pale ochraceous; spores small, 7.1–7.8 ´ 5.5–6.3 mm, with extremely low ornamentation; marginal cells tortuous and branched .................  2. L. zenkeri

   Basidiomes firmer, pale yellow ochre to pale yellowish; spores larger, 8.0–8.6 ´ 6.4–7.0 mm, ornamentation 0.2 mm high; marginal cells narrowly utriform to conical ...... 3. L. pelliculatus

 

Species descriptions

 

1. Lactarius annulatoangustifolius (Beeli) Buyck

Buyck, Bull. Jard. Bot. Nat. Belg. 59: 241 (1989). – Russula annulatoangustifolia Beeli, Bull. Jard. Bot. Etat Bxl 14: 87 (1936). – Type: Democratic Republic of Congo, Binga, 8 Nov. 1928, M. Goossens‑Fontana 834 (BR 4976–29, holotype).

     Lactarius pandani R. Heim, Candollea 7: 376 (1938). – Type: Madagascar, Betsimisaraka Prov., South of Soanierana Gagnoa, 9 Dec. 1934, R. Heim G89bis (PC, holotype).

     Lactarius pandani f. aurantiacus  R. Heim (invalid), Bull. Jard. Bot. Etat Bxl 25: 18 (1955).

     Misappl.: Lactarius zenkeri ss. Singer (1946).

 

Selected descriptions and icons. Heim, Prodr. Fl. Mycol. Madagascar 1: 37-43 & Pl. 1a (1938); Heim, Bull. Jard. Bot. Etat Bxl 25: 17–20 & Pl. 1, fig. 1a–e (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 13, fig. 4 (1955); Verbeken, Edinburgh J. Bot. 53: 72–77 (1996a); Verbeken,  Biodiversity of the genus Lactarius Pers. in tropical Africa: 143–145 & Pl. 69–76 (1996d); Karhula & al., Karstenia 38: fig. 12 (1998).

 

Pileus (10)30–50(75) mm diam., fleshy and fairly thick when young, fragile and thin when older, convex with papilla, then applanate and slightly depressed; margin thin, incurved, then straight; pellis thick, gelatinized but not glutinous, with characteristic radial to sinuous veins when young, yellow to brownish orange, darker in the centre, paler yellow-brown with faint pink tinge ('tan') at the margin, rupturing and leaving whitish fine flocks, showing an underlying striate layer, dehiscent at the margin. Secondary velum closed in the young basidiomes (development velangiocarpic), then forming a submembranaceous annulus, whitish to cream, not mobile, ring-shaped. Lamel­lae adnate to decurrent, prolonging into veins on the stipe, unequal with lamellulae of different lengths, narrow (1–3 mm), crowded, yellow to cream, then darker with pink tinge, more dirty when bruised; edge entire, concolorous. Stipe (25)35–50 × (3)6–12 mm, cylindrical, tapering downwards, slightly sinuous or curved, wrinkled when young, then smooth, with gelatinized veins in the upper part, spongy solid, then fistulous, subconcolorous with the pileus, paler cream at the apex, yellowish at the base; with whitish and abundant mycelium at the base. Context white to cream, first solid then granulose and fragile in pileus, fibrillose in stipe; taste (very) acrid; smell disagreeable, acrid. Latex abundant when young, then scarce, white; taste acrid. Spore-depo­sit white. – Pl. 1

 

Chemical reactions. Context after some minutes blue-green with gaiac, unchanging with gaiacol and pyramidon, immediately dark brown with pyrogallol, immediately purple with phenol, unchanging with Fe2SO4, &-naphtol, NH3 and anniline, reddish with sulfovanilline and brown with sulfoformol (according to Heim 1955a).

 

Basidiospores ellipsoid, 7.6–8.79.5–10.1(10.7) × 6.3–7.07.6–8.1(8.7) mm (Q = 1.14–1.241.28–1.42; n = 100); ornamentation amyloid, composed of conical to irregular warts and short ridges, < 1 mm high, often connected by fine and lower lines, forming an incomplete reticulum; surface rugose between the ornamentation; plage inamyloid. Basidia (30)35–50 × 9–13 mm, cylindrical to narrowly clavate, 4-spored, rarely 2-spored. Pleurocystidia absent. Pleuropseudocystidia rather abundant, 12–20 mm diam., emergent up to 50 mm, clavate to tortuous, tapering upwards, capitate, mucronate to rostrate; wall slightly thickened; content needle-like to granular. Lamellar edge sterile; marginal cells 12–30 × 5–10 mm, irregularly fusiform to utriform, often septate, thin-walled. Hymenophoral trama composed of sphaerocytes in the upper part, subregular and composed of narrow hyaline hyphae towards the edge of lamellae; laticiferous hyphae present, narrow. Pileipellis a lampropalisade to lamprotrichopalisade; elements of suprapellis 30–110 × 4–8 mm, long, slender, hair-shaped and tapering upwards, very thick-walled (1–2 mm), sometimes septate and branched; subpellis composed of narrow cells, 5–20 mm, slightly thick-walled to thin-walled, with some elements of the upper layer penetrating the subpellis. Stipitipel­lis a lampropalisade to lamprotricho­palisade, as pileipellis, although at the base of the stipe consisting of narrower and longer thick-walled, unbranched hyphae. Annulus composed of thin-walled, hyaline hyphae, which are densely interwoven, often septate, sometimes branched, 2–5 mm diam. Clamp-connections absent. – Fig. 25

 

Ecology. Found terrestrial or on rotten wood but connected to white mycelium and mycorrhizal roots) in drier Guineo‑Congolian rainforest with Gilbertiodendron dewevrei, Malagasy lowland rainforest, dry evergreen forest (muhulu) and wetter Zambezian miombo woodland. In Madagascar found under Uapaca louvelii and U. densifolia.

 

Distribution. Widespread in tropical Africa. Known from Cameroon, Democratic Republic of Congo, Gabon, Guinea, Liberia, Madagascar, Zambia and Zimbabwe.

 

Revised specimens

Cameroon. South Western Prov., near Mundema, Korup National Park, transect P, Jan. 1989, R. Watling 21466 (E); Ibid., Jan. 1989, R. Watling 21472 (E); Ibid., March 1989, R. Watling 24187 (E); Ibid., Jan. 1988, I. Alexander 16b (E); Ibid., trail from Mana Bridge to transect P, 12 April 1997, P. Roberts K1136 (K(M) 50411); environment of Douala, 12 Aug. 1959, Berthet 314 (LY, cited as L. pandani f. aurantiacus in Berthet & Boidin 1966).

Democratic Republic of Congo. Equateur Prov., Binga, Nov. 1928, M. Goossens-Fontana 834 (BR 4976–29, holotype); Ibid., Aug. 1929, M. Goossens-Fontana 877 (BR 4969–22); Ibid., Sept. 1940, M. Goossens-Fontana 2038 (BR 12318–96); Ibid., Oct. 1945, M. Goossens-Fontana 3061 (BR 4941–91); Tshopo Prov., 5 km NNE of Batiabongena, in humus, April 1984, B. Buyck 1344 (BR 6088–74); Ibid., May 1984, B. Buyck 1656 (BR 6094–80); Yanero, May 1984, B. Buyck 1730 (BR 6097–83); Shaba Prov., Muhulu de la Luiswishi, Dec. 1971, D. Thoen 5137 (BR 66283–32).

Gabon. Research Station of Ipassa-Makokou, 8 March 2005, B. Toirambe 1 (BR 164547–35); Ibid., 13 March 2005, S. Dibaluka Mpulusu 17 (BR 164552–40).

Guinea. Forêt humide de Ziama, arboretum des stagiaires, 12 April 2000, A. Bâ 360 (GENT).

Liberia. Near Nengbe, April 1939, G.W. Harley 57 (FH).

Madagascar. Betsimisaraka Prov., S of Soanierana Gagnoa, Dec. 1934, R. Heim G89 (PC); Ibid., R. Heim G89bis (PC, type L. pandani); Ibid.?, R. Heim s.n. (PC); Fianarantsoa, Ranomafana National Park, 1 Feb. 2000, B. Buyck & al. 00-1031, 00-1111, 00-1112 & 00-1153 (all PC); Ambotantihely, N of Ankazobe, sentier botanique, 15 Feb. 2000, B. Buyck & al. 00-1518 (PC); Toamasina Prov., station forestière Andasibe-Analamazaotra, 23 Jan. 1999, B. Buyck & G. Eyssartier 99-324 & 99-332 (all PC).

Zambia. Western Prov., Mwinilunga, road to Solwezi km 50, Jan. 1991, B. Buyck 3516, 3567-3569 & 3595 (all PC).

Zimbabwe. Manicaland Prov., Eastern Highlands, Mguzu, leg. Gansemans 5 Feb. 1999, A. De Kesel 2739 (BR 115761–40).

 

Notes. The macroscopic description is based on Heim (1938b, 1955), Singer (1946) and fieldnotes of Thoen. The microscopic description is based on Goossens-Fontana 2038, Heim G89 and Thoen 5137. The water-colours of Goossens-Fontana 834, 877 & 3061 show conspicuous (dried out?) whitish basidiomes although no microscopic differences could be found. Moreover, the exsiccata of these collections have the same colour as the other studied specimens. As a consequence we consider them conspecific. New field observations are necessary to find out whether this concerns different varieties or forms.

The species is easy to recognize, among the other annulate species, by its more prominent spore-ornamentation; the warts are up to 1 mm high, whereas the other species in the section have an ornamentation which never exceeds 0.5 mm. 

 

2. Lactarius zenkeri  (Henn.) Singer

Singer, Ann. Mycol. 40: 111 (1942). − Lactariopsis zenkeri Henn., Bot. Jahrb. Syst. 30: 51 “1901” (1902). − Type: Cameroon, Korup National Park, Jan. 1988, I. Alexander 16 (E, neotype).

     Excl.: Lactarius zenkeri ss. Singer (1946), = L. annulatoangustifolius.

 

Selected descriptions and icons. Verbeken, Edinburgh J. Bot. 53: 50–54 (1996a); Verbeken,  Biodiversity of the genus Lactarius Pers. in tropical Africa: 145–146 & Pl. 77–81 (1996d).

 

Pileus 30–60 mm diam., first convex, then applanate and infundibuliform; margin thin, incurved, then straight; pellis submembranaceous, pruinose, whitish, yellowish brown to pale ochraceous, darker in the centre, paler towards the margin, rupturing towards the margin and leaving small whitish flocks, underlaying layer smooth and striate. Secondary velum closed in the young basidiomes (development velangiocarpic), then forming an annulus near the apex of the stipe, membranaceous, thin, whitish. Lamel­lae adnate to decurrent, crowded, narrow to medium broad (1–3 mm), waxy, ochraceous, paler than pileus; edge entire, concolorous. Stipe 20–40 × 5–20 mm, cylindrical to subclavate, ochraceous, dry, smooth, paler at the apex, smooth, solid, sometimes becoming fistulous. Context firm, white, not changing; smell not remarkable. Latex quite abundant, white; taste unknown. Spore-depo­sit white.

 

Basidiospores ellipsoid, sometimes subglobose, 6.4–7.17.8–8.6 × 4.9–5.56.3–6.9 mm (Q = 1.09–1.191.29–1.45; n = 100); ornamentation amyloid, low, composed of irregular sized and shaped warts; warts less then 0.2 mm high, isolated, connected by lines or aligned, sometimes forming a faint, partial reticulum; plage mostly not amyloid, sometimes with a centrally, slightly amyloid spot. Basidia 30–40(–50) × 9–10 mm, cylindrical to slightly clavate, 4-spored, rarely 2-spored. Pleurocystidia absent. Pleuropseudocystidia rather scarce, 15–25 mm diam. in the upper part, clavate to conical, tapering upwards, mucronate, very emergent, with needle-like to granular content. Lamellar edge sterile; marginal cells 15–40 × 5–10 mm, narrowly utriform to conical, in some specimens tortuous and often dichotomously branched. Hymenophoral trama composed of sphaerocytes and numerous laticiferous hyphae; narrow, hyaline hyphae becoming more abundant near the edge. Pileipellis a lamprotrichopali­sade to lampropalisade; elements of suprapellis very thick-walled (1–2 mm), 50–110 × 4–8 mm, long, slender, hair-shaped and tapering upwards, septate and sometimes branched; subpellis composed of irregular to isodiametric cells, 5–15(–20) mm, with some elements of the upper layer penetrating. Stipitipel­lis a lamprotrichopalisade; elements of suprapellis 50–120 × 7–10 mm, very often branched, thick-walled (2–3 mm); with numerous lactifers. Annulus composed of narrow hyphae which are thin-walled, hyaline, septate and sometimes branched, (2–)3–5(–7) mm diam. Clamp-connections absent. – Fig. 26

 

Ecology. Lowland rainforest, semi‑evergreen forest with Afzelia, Uapaca bojeri woodland.

 

Distribution. Known from Cameroon, Gabon, Madagascar and Senegal.

 

Revised specimens

Cameroon. South Western Prov., near Mundema, Korup National Park, transect P16-27, Jan. 1988, I. Alexander 16 (E, neotype); Ibid., transect P23, Jan. 1989, R. Watling 21471 (E); Ibid., P23, R. Watling 21480 (E); Ibid., P18, May 1989, R. Watling 22185 (E); Ibid., trail to transect P, R. Watling 22186 (E); Ibid., P18, March 1991, R. Watling 23135 (E); Ibid., P15, R. Watling 23136 (E); Ibid., transect before P, R. Watling 23137 (E); Ibid., P13, R. Watling 23139 (E); Ibid., P21, R. Watling 25312 (E).

Gabon. Research Station of Ipassa-Makokou, 15 March 2005, A. Murhula Cizungu 20 (BR 164546–34).

Madagascar. Arivonimamo, 30 Jan. 1997, B. Buyck & al. 97-092 (PC); Ibid., 5 Feb. 1997, B. Buyck & al. 97-286 (PC).

Senegal. Basse Casamance Prov., 10 m alt., Sept. 1987, legit A. Bâ, D. Thoen 7885 (BR 66456–11).

 

Notes. The original type material (Zenker 2230, with water colour) is lost at Berlin (Horak 1968) and no isotype-material could be traced at BR, PC, K(M), E, FH or S. Singer (Singer & al., 1983) refers to "the type" of Lactarius zenkeri designating a collection from Liberia which he described as L. zenkeri, although this exsiccatum clearly represents L. annulatoangustifolius (q.v.), a species which differs particularly in having more bright orange colours and larger spores with a more pronounced ornamentation. To avoid further misunderstanding we proposed the collection Alexander 16 (E) as the neotype for Lactarius zenkeri (Verbeken 1996a). This collection was made in Korup National Park (Cameroon) where several other fungi occur which were described by Hennings from Cameroon (Watling, pers. comm.).

The macroscopic description is based on the description of Hennings (1902) and the fieldnotes from Watling. The microscopic description is based on Alexander 16, Watling 23135 and Thoen 7885.

Lactarius zenkeri is recognizable as a small and tiny annulate species with a very fragile context and small, lowly ornamented spores.

 

3. Lactarius pelliculatus  (Beeli) Buyck

Buyck, Bull. Jard. Bot. Nat. Belg. 59: 242 (1989). – Armillaria pelliculata Beeli, Bull. Soc. Roy. Bot. Belg. 59: 111 (1927). – Type: Democratic Republic of Congo, Lisala, Dec. 1925, M. Goossens-Fontana 546 (BR 7715–52, holotype).

     Lactarius pandani R. Heim f. intermedius  R. Heim, Bull. Jard. Bot. Etat Bxl 25: 20 (1955, as "var. intermedius" in Fl. Icon. Champ. Congo 4: 87 (1955), invalid.

     Lactarius pandani f. pallidus  R. Heim, Bull. Jard. Bot. Etat Bxl 25: 17 (1955), invalid.

 

Selected descriptions and icons. Heim, Bull. Jard. Bot. Etat Bxl 25: 17–23 & Pl. 1, figs. 2–4 (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 13, fig. 2a–b & 3 (1955); Verbeken, Edinburgh J. Bot. 53: 56–60 (1996); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 146–147 & Pl. 82–88 (1996d).

 

Pileus 40–80 mm diam., fleshy, firm, convex, then applanate, infundibuliform when older; margin thin, striate, first incurved, then straight; pellis viscous and with radial, gelatinized veins when wet, greyish and pellicular when dry, slightly gelatinized, ferruginous red, yellowish ochre to pale yellowish, leaving fine, whitish flocks towards the margin, dehiscent near the margin. Secondary velum closed in the young basidiomes (velangiocarp development), then forming an annulus near the apex of the stipe, membranaceous, thin, whitish. Lamellae adnate to decurrent, rather broad, rather thick, brittle, with some anastomosing veins near the margin, sometimes dichotomously branched, pale ochraceous. Stipe 30–50 × 9–14 mm, cylindrical, short, tapering downwards, smooth, with some longitudinal veins near the apex, ochraceous, paler than the pileus, fleshy, solid, then fistulous. Context white to pale yellowish; taste acrid; smell pepper-like. Latex scarce, transparent, watery, not present in older basidiomes; taste acrid to very acrid. Spore-deposit white. (According to Heim 1955a). – Pl. 2 

 

Basidiospores ellipsoid, 7.1–8.08.6–9.1(–9.9) × 5.8–6.47.0–7.5(–8.3) mm (Q = 1.13–1.231.24–1.35, n = 60); ornamentation amyloid, composed of irregularly sized and shaped warts; warts less then 0.5 mm high, isolated, connected by lines or aligned, sometimes forming a faint, partial reticulum, warts always distinct; plage inamyloid. Basidia 40–50 × 9–10 mm, cylindrical to slightly clavate, 4-spored, rarely 2-spored. Pleurocystidia absent. Pleuropseudocystidia rather scarce, 15–25 mm diam. in the upper part, clavate to conical, tapering upwards, mucronate, very emergent, with needle-like to granular content. Lamellar edge sterile; marginal cells 15–40 × 5–10 mm, narrowly utriform to conical. Hymenophoral trama composed of sphaerocytes and numerous laticiferous hyphae; narrow, hyaline hyphae becoming more abundant near the edge. Pileipellis a lamprotricho­palisade; elements of suprapellis very thick-walled (1–2 mm), 50–130 × 4–8 mm, long, slender, hair-shaped and tapering upwards, septate and sometimes branched; subpellis composed of irregular to isodiametric cells, 5–15(–20) mm, with some elements of the upper layer penetrating. Stipitipel­lis a lamprotrichopalisade to lampropalisade, with larger isodiametric cells than the pileipellis; elements of suprapellis 50–150 × 7–10 mm, sometimes branched, with 2–3 mm thick walls; with numerous lactifers. Annulus composed of narrow hyphae which are thin-walled, hyaline, septate and sometimes branched, (2–)3–5(–7) mm diam. Clamp-connections absent. – Fig. 27

 

Ecology. Guineo‑Congolian rainforest, Uapaca woodland.

 

Distribution. Known from Democratic Republic of Congo, Gabon, Guinea and Madagascar.

 

Revised specimens

Democratic Republic of Congo. Equateur Prov., Lisala, 350-400 m alt., on the ground, Dec. 1925, M. Goossens-Fontana 546 (BR 7715–52, holotype); Binga, 380 m alt., Aug. 1928, M. Goossens-Fontana 807 (BR 12321–02); Ibid., Dec. 1941, M. Goossens-Fontana 2069 (BR 12320–01); Ibid., Oct. 1942, M. Goossens-Fontana 3036 (BR 12319–00).

Gabon. Research Station of Ipassa-Makokou, 16 March 2005, S. Dibaluka Mpulusu 28 (BR 164539–27); Ibid., 16 March 2005, A. Murhula Cizungu 21 (BR 164546–34).

Guinea. Forêt humide de Ziama, arboretum des stagiaires, July 1999, A. Bâ 62 (GENT).

Madagascar. Toamasina, RN7, 32 km after Antsirabe, Fiadanana village, 10 Feb. 2000, B. Buyck & al. 00-1335 (PC); Ambotantihely, N of Ankazobe, sentier botanique, 15 Feb. 2000, B. Buyck & al. 00-1389a (PC).

 

Notes. Lactarius pelliculatus is very closely related to L. zenkeri, but differs by the somewhat larger basidiomes (pileus up to 8 cm diam.) and the slightly larger spores. The marginal cells are not tortuous or branched, as is often the case in Lactarius zenkeri. The ornamentation of the spores is more pronounced than in Lactarius zenkeri, although still very low and faint when compared to L. annulatoangustifolius.

Buyck (1989a) synonymized Lactarius pandani R. Heim with L. pelliculatus (Beeli) Buyck, without any comment. It has been demonstrated that only part of the specimens described as Lactarius pandani (“f. pallidus” and “f. intermedius”) is conspecific with L. pelliculatus, while the type of L. pandani and a specimen described as L. pandani f. aurantiacus represent L. annulatoangustifo­lius (Verbeken 1996a).

 

4. Lactarius heimii  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 201 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 30 March 1994, A. Verbeken 94465 (BR 57671–53, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 147–149 & Pl. 89–92 (1996d); Karhula & al., Karstenia 38: fig. 13 (1998); Härkonen & al., Norrlinia 10: 87 (2003).

 

Pileus 30–90 mm diam., firm and fleshy, convex to planoconvex, depressed in the centre; margin strongly involute when young, then deflexed downwards; pellis very thin, arachnoid, pruinose, greyish orange to brownish orange (5AB3–8, 6BC3–5), rather pale yellow (4A4–5) near the margin, orange white to light yellow or dark orange when young (4A4–5, 6A2), rupturing at the margin, showing a more shiny underlaying layer. Secondary velum forming an annulus near the apex of the stipe, arachnoid, thin, whitish. Lamel­lae adnate to slightly decurrent, unequal with lamellulae, moderately distant (L+l = 6+6 to 8+2/cm), medium broad (2–4 mm), thin, fragile, yellowish white, 3A2–3; edge concolorous, entire. Stipe 25–35 × 8–15 mm, cylindrical, slightly tapering downwards, felty, dry, orange white to cream (5A2), firm and solid. Context firm, (1)2–3 mm in the pileus, white to cream, unchanging; taste spicy to very acrid; smell agreeable, sweet. Latex not abundant, white or watery, taste mild or bitter to more or less acrid. Spore-depo­sit white. – Pl. 3

 

Chemical reactions. Context greenish (Buyck 3200) or unchanging  (Verbeken 94-465) with FeSO4; blue-green with gaiac (Buyck 3200).

 

Basidiospores ellipsoid to elongate, 7.6–8.710.7–11.6 × 5.9–6.77.4–8.3 mm (Q = 1.16–1.301.49–1.64; n = 240); ornamentation amyloid, very dense, composed of low warts and ridges, < 0.2 mm high, aligned and connected by fine lines, forming an incomplete to almost complete reticulum with very small meshes; plage inamyloid. Basidia 45–55 × 10–12 mm, subclavate, 4-spored. Pleurocystidia absent. Pleuropseudocystidia scarce, 10–18 mm diam., emergent up to 50 mm, cylindrical, obtuse and with rounded apex; content densely granular; some pseudocystidia connected with oleiferic hyphae, 5–7 mm diam., content oleiferic. Lamellar edge sterile; marginal cells 15–25 × 7–11 mm, shortly cylindrical to clavate, thin-walled, sometimes septate. Hymenophoral trama composed of sphaerocytes and hyaline hyphae; lactifers abundant and up to 15 mm diam. Pileipellis a lamprotrichopalisade; elements of suprapellis (10–)30–200 × 5–10 mm, short and subclavate or long, slender, cylindrical and hair-shaped, often septate and branched, very thick-walled, 2–3(–4) mm; subpellis composed of irregular to isodiametric elements, very poorly developed with a lot of penetrating elements from suprapellis who are connected with hyaline, thin-walled hyphae. Stipitipel­lis a lamprotrichopalisade, as pileipellis. Annulus composed of interwoven, hyaline, thin-walled hyphae, 4–6(–9) mm diam., septate and sometimes branched. Clamp-connections absent. – Fig. 28

 

Ecology. Zambezian miombo woodland. Collected under various trees such as Brachystegia, Baphia, Parinari, Isoberlinia, Uapaca, Albizia, Julbernardia, Marquesia.

 

Distribution. Known from Burundi, Malawi, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, Dec. 1993, B. Buyck 5358; Ibid., March 1994, A. Verbeken 94-003 (BR 57555–34), 94-115 (BR 57598–77), 94-158 (BR 57612–91), 94-209 (BR 57619–01), 94-210 (BR 57620–02), 94-440 (BR 57666–48) & 94-465 (BR 57671–53, holotype; GENT, isotype); Ibid., April 1994, A. Verbeken 94-560 (BR 57703–85); Nkayamba, just N of Rumonge, Dec. 1991, B. Buyck 4050 & 4051 (all PC); Ibid., Jan. 1992, B. Buyck 4187 (PC); Ibid., March 1992, B. Buyck 4239 & 4285 (all PC); Ibid., Dec. 1992, B. Buyck 4652 (PC); Ibid., B. Buyck 4686 & 4724 (all PC); Ibid., Jan. 1993, B. Buyck 4849 (PC); Ibid., Feb. 1993, B. Buyck 4972 (PC); Mugara, Nov. 1978, J. Rammeloo 5868 (BR 8779–49) & 5908 (BR 8773–43); Ibid., Dec. 1978, J. Rammeloo 5997 (BR 18928–13), 6006 (BR 18927–12) & 6073 (BR 8777–47).

Malawi. Central Prov., Dedza distr., Chongoni, 11 Feb. 1972, Williamson 594 (K(M) 38476).

Tanzania. Western Prov., Kahama distr., Mpunze, Forest Reserve, 10 Dec. 1991, T. Saarimäki & al. 1034 & 1042 (all H); Ibid., Tabora distr., Lulanguru, 14 Dec. 1991, T. Saarimäki & al. 1111 (H); Southern Highlands Prov., Iringa distr., Itagutwa, 40 km NE of Iringa, 8 Feb. 1993, T. Saarimäki & al. 1600 (H).

Zambia. Copperbelt Prov., Chati‑forest, near Kitwe, Dec. 1990, B. Buyck 3122, 3127, 3139, 3159, 3162, 3189, 3191 & 3200 (all PC); Ibid., B. Buyck 3203 & 3209b (all PC); Luapala Prov., Mansa, Kwanfumwe, 2 Jan. 1991, B. Buyck 3316 (PC); Kabunda mission, 3 Jan. 1991, B. Buyck 3354 & 3355 (all PC); Western Prov., Mwinilunga, 29 Jan. 1991, B. Buyck 3515 (PC).

Zimbabwe. Midlands Prov., Mvuma, Central Estates, south side of Beacon Hill, 27 Jan. 1999, A. Verbeken 99-029 (GENT); Ibid., Baru section, 27 Jan. 1999, A. Verbeken 99-036 (GENT); Midlands Prov., Mvuma, Mtao forest, 28 Jan. 1999, A. Verbeken 99-044 (GENT); Ibid., 11 Feb 1999, A. De Kesel 2451 (BR 112621–04) 

 

Notes. The macroscopic description is based on fieldnotes of Rammeloo, Verbeken & Buyck. The microscopic description is based on Verbeken 94-465, 94-210, 94-003 and Buyck 3189.

    Among the other annulate species, Lactarius heimii is easily recognized by its elongate spores which are ornamented with a dense, almost complete reticulum with hardly any warts distinguisha­ble.

     This species is consumed by some local populations (Karhula & al. 1998, Verbeken & al. 2000).

 

5. Lactarius velutissimus Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 212 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 23 March 1994, A. Verbeken 94-291 (BR 57639–21, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 149–150 & Pl. 93–96 (1996d); Karhula & al., Karstenia 38: fig. 14 (1998); Ryvarden & al., An introduction to the larger fungi of South Central Africa: 100 (1994, as Lactarius pandani); Verbeken, Micol. Veget. Medit. 16: fig. 6 (2001).

 

Pileus 45–140 mm diam., first convex, then applanate and planoconcave to infundibuliform; margin involute when young, straight and even deflexed upwards when older, then sometimes striate; pellis thick, felty, pale orange to light yellow in the centre (4A3–5A3), yellowish white (4A2) towards the margin, rupturing star-shaped and showing a shiny, striate, somewhat darker layer. Secondary velum forming an annulus near the apex of the stipe, membranaceous, arachnoid when older, not mobile, white to cream (4A2). Lamel­lae decurrent, unequal with a few lamellulae of different lengths, sometimes dichotomously branched, waxy to fragile, thin, pale yellow to light yellow (3A2–3 to 4A2–4); edge concolorous, entire. Stipe 25–35 × 6–17 mm, shortly cylindrical, tapering downwards, felty, pale orange, light orange to cream (4A3–5A3). Context firm, 4–6 mm in the pileus, solid in stipe, white, changing light orange in the base of the stipe; taste acrid; smell agreeable. Latex rather abundant, white, taste acrid. Spore-depo­sit white. – Pl. 4

 

Chemical reactions. Context pale orange with FeSO4.

 

Basidiospores ellipsoid, 7.6–8.49.2–10.4 × 6.3–6.87.2–8.1 mm (Q = 1.15–1.211.32–1.40; n = 100); ornamentation amyloid, composed of irregularly sized and shaped warts and ridges, sometimes aligned, sometimes connected by fine lines, never forming a reticulum, < 0.2 mm high, wall between the ornamentation rugose; plage inamyloid. Basidia 48–60 × 9–10 mm, subclavate, 4-spored; content guttate or needle-like. Pleurocystidia absent. Pleuropseudocystidia not abundant, 12–15 mm diam., emergent up to 30 mm, fusiform, tapering upwards, mucronate; content granular and needle-like. Lamellar edge sterile; marginal cells 15–25 × 8–12 mm, shortly cylindrical or clavate, sometimes septate. Hymenophoral trama composed of sphaerocytes and hyaline hyphae, lactifers abundant. Pileipellis a lamprotrichopalisade; elements of suprapellis (20–)50–200 × 5–6(–10) mm, short and clavate or long, slender and hair-shaped, often septate and branched, very thick-walled, 2–3(–4) mm; subpellis composed or irregular to isodiametric elements, sometimes slightly thick-walled. Stipitipel­lis a lamprotrichopalisa­de, as pileipellis; elements of suprapellis 60–200 × 4–6 mm. Annulus composed of narrow hyphae, thin-walled, hyaline, septate and sometimes branched. Clamp-connections absent. – Fig. 29

 

Ecology. Zambezian miombo woodland.

 

Distribution. Known from Burundi, Democratic Republic of Congo, Kenya, Malawi, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, Dec. 1993, B. Buyck 5358b; Ibid., March 1994, A. Verbeken 94-007 (BR 57559–38), 94-075 (BR 57585–64), 94-291 (BR 57639–21, holotype; GENT, isotype) & 94-439 (BR 57665–47); Cankuzo Prov., Murango, March 1994, B. Nzigidahera 58 & 61 (all PC).

Democratic Republic of Congo. Shaba region, Kipopo, 1250 m alt., 5 Dec. 1971, D. Thoen 5084 (BR 66272–21); Luiswishi, terrestrial, Feb. 1986, J. Schreurs 1121 (BR 7954–00) & 1165 (BR 7982–28); Fungurume, 1350 m alt., 26 Feb. 1986, J. Schreurs 1211 (BR 8015–61).

Kenya. Coast Prov., Kwale distr., Arabuko-Sokoke Forest Reserve, plot 5, 15 May 1987, M.H. Ivory 674 (K(M) 38466); Ibid., plot 1, 29 Nov. 1994, M.H. Ivory 5036 (BR 49371–95).

Malawi. Northern Prov., Mzimba distr., Mtanga tanga Forest, 15 March 2005, F. Noe 05/538, (GENT); Ibid., Ntanga Forest Reserve, 30 Jan. 2005, A. Verbeken 05-147 (GENT); Ibid., Perekezi Forest Reserve, 28 Jan. 2005, A. Verbeken 05-093 (GENT); Ibid., 29 Jan. 2005, F. Noe 05/11 (GENT); Ibid., 13 Feb. 2005, F. Noe 05/225 (GENT); Ibid., 18 Feb. 2005, F. Noe 05/351 (GENT); Ibid., 9 March 2005, F. Noe 05/453 (GENT); Ibid., 11 March 2005, F. Noe 05/496 (GENT); Ibid., 16 March 2005, F. Noe 05/615 (GENT); Southern Prov., Machinga distr., Liwonde Forest Reserve, 22 Jan. 2005, A. Verbeken 05-019 (GENT).

Tanzania. Southern Prov., Songea distr., 29 km from Songea towards Mbinga, 29 Jan. 1993, T. Saarimäki & al. 1454 (H); Southern Highlands, Njombe distr., Mbalali village, 11 km S of Kidugala, 1 Feb. 1993, T. Saarimäki & al. 1515 (H).

Zambia. Copperbelt Prov., Misaka Forest Reserve, near Kitwe, April 1991, R. Watling 25920 (E); Feb. 1982, G. Piearce FP712/1 (K(M) 38498); Luapala Prov., near Kawamba, road near Ntumbachushi falls, 3 Jan. 1991, B. Buyck 3431 (PC); Mansa, Kabunda mission, 6 Jan. 1993, B. Buyck 3353 (PC); Western Prov., Mwinilunga, 29 Jan. 1991, B. Buyck 3507 (PC); Northern Prov., Mpika distr., North Luangwa National Park, Mwaleshi camp, 18 Jan. 1995, D. Shah‑Smith 126 (K(M) 35510); farm Gibsons, 20 Jan. 1996, B. Buyck & G. Eyssartier 96-147 (PC); Chibuli, 31 Jan. 1996, B. Buyck & G. Eyssartier 96-254 (PC).

Zimbabwe. Manicaland Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-185 (GENT).

 

Notes. The macroscopic description is based on fieldnotes of Verbeken and Schreurs; the microscopic description is mainly based on the specimens collected by Verbeken in Burundi and Zimbabwe.

     The species is characterized by the very thick, whitish and stellately rupturing pileipellis, which even in exsiccata remains recognizable.

     This species is locally eaten in the miombo area (e.g. Karhula & al. 1998). 


Sect. Chamaeleontini  Verbeken

 

Lactarius sect. Chamaeleontini Verbeken, Mycotaxon 66: 393 (1998)

Type species: Lactarius chamaeleontinus R. Heim

 

Note. The distinction between this section and L. sect. Lactariopsis is based on absence versus presence of annular veil. This grouping is artificial but maintained for practical reasons.

 

Key to tropical African species

 

1.  Hymenial leptocystidia rather abundant, 65–80 × 8–10 µm, cylindrical to subclavate, moniliform to rostrate. Veil present in young basidiomes as an arachnoid indusium between the stipe and the margin of the pileus, sometimes remaining as a very small annulus in older basidiomes; thick-walled hair-shaped elements in the pileipellis (very) scarce; context changing pinkish or reddish, then greyish green .............................................................. 6. L. indusiatus

     Pleurocystidia absent; thick-walled hair-shaped elements in pileipellis absent to abundant; velar remnants never forming an annulus or absent ..................................................  2

 

2.  Pileipellis without thick-walled elements .................................................................  10. L. laevigatus

     Pileipellis with more or less abundant hair-shaped, thick-walled elements, sometimes difficult to find ................... 3

 

3.  Fruit body firm; cap dirty white to yellowish cream, often covered with soil particles ........ 13. L. emergens

     Not with this combination of characters .............................................................  4

 

4.  Young cap and stipe entirely whitish pruinose, thick-walled terminal elements in pileipellis numerous ........ 11. L. pruinatus

     Cap and stipe not entirely pruinose, thick-walled terminal elements of the pileipellis scarce or numerous ......................... 5

 

5.  Small species, cap < 2 cm diam.; all terminal elements of pileipellis thick-walled, subfusiform to subcylindrical, 15–35 × 6–9 µm, spores on average 10 µm long  ....................  12. L. uapacae

     Cap most often > 2 cm diam.; thick-walled elements in pileipellis scattered, longer and slender, spores on average shorter ...  6

 

6.  Basidiocarp more or less entirely bright yellowish orange, often sticky; pseudocystidia tapering or finely capitate. Species associated with Brachystegia spp. ...................  14. L. brachystegiae

     Basidiocarp differently coloured; pseudocystidia not finely capitate ..............................................  7

 

7.  Spore ornamentation low, not more than 0.2 µm high ..........................................  9. L. sesemotani

     Spore ornamentation up to 0.5 µm high ................................................  7

 

8.  Pileus up to 5 cm diam., thin and fragile, pale orange, ochraceous or reddish brown; margin regularly striate to grooved .......................................................................  7. L. chamaeleontinus

     Pileus up to 8 cm diam., firmer, pale to straw yellow; margin irregular .......  8. L. madagascariensis


Species descriptions

 

6. Lactarius indusiatus  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 201 (1996). – Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 11 March 1994, A. Verbeken 94–122 (BR 57599–78, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 151-152 & Pl. 97-99 (1996d); Verbeken, Mycotaxon 55: 394-399 (1998).

 

Pileus 30–65 mm diam., rather thick, firm, convex to applanate, then infundibuliform; margin involute when young, then straight, sometimes slightly crenulate; pellis not or hardly dehiscent, smooth, soon desiccating, greyish orange to pale orange or leather-brown in the centre (6E4–5) and greyish yellow (4B3–4) near the margin. Lamellae slightly decurrent, unequal with lamellulae of different lengths (1–3 lamellulae between two lamellae), rather distant (L+l = 4+2/cm), moderately broad (2–4 mm), thick, firm, tough, without venation, very seldom dichotomously branched, orange-yellow, pale orange to light orange (5A3–4); edge entire, slightly darker. Stipe 24–43 × 7–19 mm, cylindrical, rather short and broad, slightly tapering downwards, smooth, greyish orange to pale orange, brownish orange (5C3) near the base, yellowish grey (4B2) in the upper part or paler towards the base and the apex, firm, solid. Context firm, white, changing salmon pink or dull red (8C3), greyish green when cut or bruised; smell agreeable, sweet; taste acrid, burning. Latex scarce, white; taste acrid. Velum present in young specimens as an arachnoid indusium between the stipe and the margin of the pileus; sometimes remaining as a small annulus in the older specimens. Spore-deposit not observed. – Pl. 4

 

Chemical reactions. Context unchanging with FeSO4.

 

Basidiospores subglobose to ellipsoid, 6.9–7.88.2–9.1 × 5.5–6.37.0–8.0 mm (Q = 1.09–1.161.22–1.38, n = 40); almost smooth; ornamentation very faint, composed of some very small warts and ridges; plage inamyloid. Basidia (50–)60–80 × 8–9(–10) mm, cylindrical, long, slender, 4-spored, sometimes 2-spored. Pleuroleptocystidia rather abundant, 65–80 × 8–10 mm, cylindrical to subclavate, moniliform to rostrate, thin-walled to slightly thick-walled; content guttate. Pleuropseudocystidia abundant, 6–9 mm diam., cylindrical to subfusiform, tapering upwards, often emergent; content oleiferic, slightly needle-like. Lamellar edge sterile; marginal cells long, slender, cylindrical, with rounded apex, 20–35 × 3–5(–6) mm, often septate, thin-walled, hyaline; pseudocystidia present. Hymenophoral trama composed of sphaerocytes and rather abundant lactifers. Pileipellis a mixed trichopalisade; terminal elements 10–20(–25) × 4–10(–12) mm, subclavate to clavate, thin-walled, hyaline; hair-shaped, thick-walled elements scarce, but present. Stipitipellis a trichoderm; terminal elements 15–50(–60) × 4–6 mm, long, cylindrical or tapering upwards, thin-walled or slightly thick-walled, hyaline, recumbent or ascending. Velum composed of long, narrow, parallel, thin-walled hyphae, 2–4(–5) mm diam., septate. Clamp-connections absent. – Fig. 30

 

Ecology. Miombo woodland.

 

Distribution. Only known from Burundi.

 

Revised specimens

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, 11 March 1994, A. Verbeken 94-122 (BR 57599–78, holotype; GENT, isotype); Nkayamba, just N of Rumonge, 12 March 1992, B. Buyck 4211 (PC); Ibid., 26 March 1992, B. Buyck 4290 (PC).

 

Notes. The macroscopic description is based on fieldnotes of Verbeken. The microscopic description is based on Verbeken 94-122, Buyck 4211 & 4290.

     Besides the presence of an indusium, Lactarius indusiatus differs especially from L. laevigatus by the changing context, the longer basidia, the extremely lowly ornamented spores, the immediately burning acrid context and the presence of thick-walled hairs in the pileipellis.

 

7. Lactarius chamaeleontinus R. Heim

Heim, Bull. Jard. Bot. Etat Bxl 25: 87 (1955). – Type: Democratic Republic of Congo, Binga, 11 April 1934, M. Goossens-Fontana 942 (BR 7721–58, holotype).

 

Selected descriptions and icons. Heim, Bull. Jard. Bot. Etat Bxl 25: 87–89 & Pl. 6, fig. 4a–c (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 15, fig. 8 (1955); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 156–157 & Pl. 107–109 (1996d).

 

Pileus 20–40(–50) mm diam., thin, convex, then depressed; margin inflexed, deeply, regularly striate to grooved; pellis dehiscent, dry, very finely tomentose, pale orange, ochraceous or reddish brown. Lamellae adnate to decurrent and even prolonging on the stipe, unequal with lamellulae of different lengths (one lamellula between two lamellae), sometimes dichotomously branched, distant (L+l = 3+1 to 3+2/cm), rather broad (3–7 mm), thin, brittle, pale yellow, pale orange, ochraceous yellow; edge entire, concolorous. Stipe 40–65 × 3–8 mm, cylindrical, slender, sometimes sinuose, tapering downwards, very finely tomentose, pale orange, ochraceous or reddish brown, whitish at the apex and at the base, soon fistulous. Context granular, spongy, brittle, white, unchanging. Latex white, becoming ochraceous. Spore-deposit white. – Pl. 5

 

Chemical reactions. Context between orange and green with FeSO4, intense and soon blue-green with gaiac (Goossens-Fontana 4030), faintly and slowly blue-green with gaiac (Buyck 3218), unchanging with NH4OH, slowly violet-blue with phenol (Goossens-Fontana 4030).

 

Spores subglobose to ellipsoid, 8.8–9.4–9.5–10.3(10.5) × (6.8)7.0–7.7–8.3–8.8 mm (Q = 1.06–1.15–1.23–1.35, n = 60); ornamentation amyloid, composed of irregularly sized and shaped warts, up to 0.5 mm high, sometimes aligned, mostly connected by fine connective lines, forming an incomplete reticulum; wall rugose, slightly amyloid; plage sometimes with a central amyloid spot. Basidia 45–50 × 10–13 mm, subclavate to clavate, 4-spored, rarely 2-spored; content guttate, sometimes needle-like. Pleurocystidia absent. Pleuropseudocystidia scarce, emergent, 12–16 mm, subclavate or fusiform, rounded or tapering at apex, sometimes mucronate; content oleiferic, guttate. Lamellar edge sterile; marginal cells 20–35 × 5–10(12) mm, subcylindrical, clavate, fusiform or irregularly tortuous, often septate, thin-walled, hyaline. Hymenophoral trama composed of sphaerocytes and lactifers. Pileipellis a mixed trichopalisade; suprapellis composed of short clavate to subcylindrical, thin-walled, hyaline elements, 10–15(30) × 5–10(15) mm, forming chains; and long, slender, hair-shaped, thick-walled elements, 20–90(110) × 4–7 mm; subpellis ixocutis-like, composed of slender, narrow, thin-walled, more or less parallel hyphae, 2–4 mm diam. Stipitipellis a cutis, with some arising, hair-shaped, thick-walled terminal elements, 20–90(120) × 4–7 mm; lactifers abundant. Clamp-connections absent. – Fig. 31

 

Ecology. Found in different forest types, such as Guineo-Congolian rainforest with Gilbertiodendron dewevrei, wetter Zambezian miombo woodland (found under Brachystegia, Baphia, Julbernardia etc.), dry Sudanian woodland with Afzelia africana.

 

Revised specimens

Benin. Atacora Prov., Bassila, 4 Oct. 2000, A. De Kesel 2998 (BR 129210–06).

Democratic Republic of Congo. Equateur Prov., Binga, 11 Apr. 1931, M. Goossens-Fontana 942 (BR 7721–58, holotype); Ibid., Dec. 1945, M. Goossens-Fontana 4030 (BR 5002–55).

Zambia. Copperbelt Prov., Chati‑forest near Kitwe, 21 Dec. 1990, B. Buyck 3218 (PC); Ibid., 22 Dec. 1990, B. Buyck 3235, 3245 & 3246 (all PC); Ibid., 14 Jan. 1991, B. Buyck 3472 (PC); Western Prov., Mwinilunga, road to Solwezi, km 50, 30 Jan. 1991, B. Buyck 3534 (PC).

 

Notes. The type-specimen consists of small pieces of basidiomes and is in very bad condition. The macroscopic description is based on the fieldnotes of Goossens-Fontana 942 & 4030 and Buyck 3218. The microscopic description is based on Goossens-Fontana 942 & 4030 and Buyck 3218 & 3534.

     The taste and smell of the context is described as acrid (?) in Goossens-Fontana 942; mild, then slightly acrid in Goossens-Fontana 4030. In Buyck 3218 the taste is said to be mild, the smell particular and chemical.

     The Zambezian specimens have slightly larger basidiomes and the stipe is not as slender.

     This species looks like a small version of Lactarius sesemotani, from which it also differs by the clearly bigger spores.

 

8. Lactarius madagascariensis Verbeken & Buyck

Buyck & al., Mycol. Res. 111: 791 (2007). – Type: Madagascar, Ranomafana National Park, 3. Feb. 1999, B. Buyck & G. Eyssartier 99-417 (PC, holotype; GENT, isotype).

 

Pileus 40–80 mm diam., planoconcave, soon depressed to irregular infundibuliform; surface smooth, shiny, pale to straw yellow, darker in the center, paler near the margin; margin distinctly and strongly striate to sulcate, up to half of the pileus radius. Stipe 24–44 × 12–16 mm, cylindric, concolorous with pileus or slightly paler. Lamellae broadly adnate to decurrent and decurrent with tooth, concolorous with pileus, very distant, with lamellulae, locally irregularly forked and with anastomosing veins, very broad (up to 1 cm). Context whitish to pale yellowish, unchanging, thin-fleshy in pileus, brittle in stipe; taste mild; smell not remarkable. Latex absent. – Pl. 5

 

Spores broadly ellipsoid, 8.0–8.6–8.9–10.1 × 6.6–7.3–7.5–8.5 µm (Q = 1.08–1.19–1.20–1.32, n = 40); ornamentation amyloid, composed of low, irregular warts, up to 0.5 µm high, sometimes aligned, but rarely connected with thin ridges; plage not amyloid. Basidia 50–65 × 9–11 µm, subclavate, 4-spored; sterigmata 6–9 × 2–3 µm. Pleurocystidia absent. Pleuropseudocystidia rare, slightly emergent, irregularly cylindrical, 7–11 µm diam., with rounded, slightly tapering apex, with dense, needle-like content. Lamellar edge sterile; marginal cells 12–35 × 5–8 µm, cylindrical, somewhat irregular and slightly tortuous, thin-walled, hyaline. Hymenophoral trama cellular. Pileipellis an irregular and loosely interwoven cutis to trichoderm, up to 100 µm thick, with abundant, thick-walled, septate hyphae orientated in all directions. Stipitipellis an irregular and loosely interwoven, thin cutis, resting on a layer of sphaerocytes. Clamp-connections absent. – Fig. 32

 

Ecology. Associated with Uapaca louvellii in wet mountain forest.

 

Distribution. Only know from the type locality.

 

Revised specimens

Madagascar. Ranomafana National Park, 3 Feb. 1999, Buyck & Eyssartier 99-409 (PC), 99-417 (PC, holotype; GENT, isotype), 99-424, 99-431 & 99-432 (all PC).

 

Notes. Lactarius madagascariensis differs from L. chamaeleontinus by the somewhat larger, firmer and paler basidiocarps and the more irregular cap margin, which is regularly striate to grooved in L. chamaeleontinus. The spores of L. madagascariensis are somewhat shorter (compared to 8.8–9.4–9.5–10.5 µm long in L. chamaeleontinus) and the pileipellis lacks the rounded to short clavate cells present in L. chamaeleontinus. Lactarius madagascariensis shares most of its field-characters with L. sesemotani, from which it is easily distinguished by the heavier ornamented spores: spore ornamentation of L. sesemotani never exceeds 0.2 µm height, while the spore ornamentation in L. madagascariensis is composed of warts up to 0.5 µm. In the field, Lactarius madagascariensis could be mistaken also for a representative of Russula sect. Archeinae. This is due to a general similarity in habitus and to the absence of latex exudation in this species. Microscopically, the abundance of lactifers in the gill trama places this species unambiguously in the genus Lactarius.

 

9. Lactarius sesemotani  (Beeli) Buyck

Buyck, Bull. Jard. Bot. Nat. Belg. 59: 241 (1989). – Russula sesemotani Beeli, Bull. Soc. Roy. Bot. Belg. 60: 169 (1928). − Type: Democratic Republic of Congo, Diobo Akuba, Dec. 1925, M. Goossens-Fontana 505a (BR 5019–72, lectotype).

 

Selected descriptions and icons. Verbeken, Edinburgh J. Bot. 53: 66–69 (1996); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 153–155 & Pl. 100–103 (1996d).

 

Pileus 50–100(130) mm diam., thick, fleshy, hemispherical to convex when young, then applanate and infundibuliform; margin incurved when young, straight when older, strongly and deeply sulcate; pellis dehiscent, smooth, shiny, viscose, finely fibrous in the centre, yellowish ochre, then ochraceous brown (4A4–7 to 5AB4), paler towards the margin (3A2), greyish when older. Lamel­lae adnate, decurrent when older, unequal with a few lamellulae (0–1 between 2 lamellae), fairly distant (L+l = 3+1 to 5+1/cm), rather broad (7–9 mm), rather thick, sometimes forked, cream to pale yellowish (4A3–4); edge entire, concolorous. Stipe (25)40–100 × 15–25 mm, cylindrical, subbulbous, faintly striate, faintly velvety, whitish, pale ochre, firm, solid, later sometimes fistulous. Context firm, white to cream, unchanging, but turning pale orange under the pileipellis; taste mild, but then acrid by the latex; smell not remarkable, agreeable. Latex scarce, white, fluid; taste acrid. Spore-depo­sit pale, but not purely white. – Pl. 6

 

Chemical reactions. Context unchanging or faintly greyish brown with FeSO4, unchanging with HCl, NaOH and NH4OH.

 

Basidiospores mostly ellipsoid, sometimes subglobose, 7.2–8.28.6–9.7 × 5.6–6.77.2–7.9 mm (Q = 1.09–1.191.24–1.43; n = 80); ornamentation amyloid, composed of irregularly shaped and sized warts, aligned or connected by fine lines, never forming a reticulum, not exceeding 0.2 mm height; plage sometimes with a faintly amyloid spot in the centre. Basidia 35–40 × 8–10 mm, cylindrical to subclavate, 4-spored, sometimes 2-spored. Pleurocystidia absent. Pleuropseudocystidia rather scarce, 8–12 mm diam., cy­lindrical to fusiform, with rounded or tapering apex, emergent up to 30 mm; content oleiferic or granular and needle-like. Lamellar edge sterile; marginal cells 15–40 × 5–8 mm, fusiform, tapering upwards, often septate, sometimes branched. Hymenophoral trama composed of sphaerocytes and lactifers. Pileipellis a mixed trichopalisade; suprapellis composed of cylindrical or isodiametric to fusiform, hyaline elements, 10–20 × 5–8 mm, and hair-shaped, slender, long, slightly tortuous elements with thickened wall (1 mm), 50–120 × 4–8 mm, sometimes branched; subpellis composed of loosely interwoven, hyaline hyphae, (1)2–3 mm diam., forming an ixocutis. Stipitipel­lis a cutis with some ascending, hair-shaped, thick-walled terminal elements, 20–100 × 4–7 mm; lactifers abundant. Clamp-connections absent. – Fig. 33

 

Ecology. Found in several forest types, such as swamp forest, drier Guineo-Congolian rainforest, wetter Zambezian miombo woodland.

 

Distribution. Widespread in tropical Africa. Known from Burundi, Democratic Republic of Congo, Ivory Coast, Malawi, Zambia and Zimbabwe.

 

Revised specimens

Burundi. Bururi Prov., Nyamirambo, near Rumonge, March 1994, A. Verbeken 94-082 (BR 57592–71), 94-154 (BR 57608–87), 94-155 (BR 57609–88), 94-471 (BR 57677–59) & 94-476 (BR 57682–64).

Democratic Republic of Congo. Equateur Prov., Eala, May 1923, M. Goossens-Fontana 143a (BR 5020–73); Djongo Akuba, Dec. 1925, M. Goossens-Fontana 505a (BR 5019–72, lectotype); Shaba Prov., Mengé, 4 April 1986, J. Schreurs 1592 (BR 8761–31).

Ivory Coast. Abidjan Prov., Forêt du Bianco, 4 Jan. 1976, Aké Assi 435 (K(M) 38465).

Malawi. Northern Prov., Mzuzu distr., Katoto E, 31 March 1973, Pawek in J. Williamson 638 (K(M) 38479).

Zambia. Copperbelt Prov., Chati forest, 14 Jan. 1991, B. Buyck 3471 (PC); Western Prov., Mwinilunga, road to Solwezi km 50, 30 Jan. 1991, B. Buyck 3531 (PC); Northern Prov., Mpika distr., North Luangwa National Park, Mwaleshi camp, 9 Feb. 1995, D. Shah‑Smith 199 (K(M) 35504); Chibuli, 31 Jan. 1996, B. Buyck & G. Eyssartier 96-249 (PC).

Zimbabwe. Mashonaland East Prov., Bromley, Liemba farm, 3 Feb. 1999, A. Verbeken 99-107 (GENT); Manicaland Prov., Eastern Highlands, Mguzu, 5 Feb. 1999, A. De Kesel 2409 (BR 112579–59).

 

Notes. The original description has been based on a heterogeneous exsiccatum. Both Goossens-Fontana 143 & 505 are a mixture of Russula and Lactarius material. One water-colour of Goossens-Fontana 505 represents clearly the Lactarius, the water-colour of Goossens-Fontana 143 represents a smaller Russula. We separated the collections renumbering the material as Goossens-Fontana 143a & 143b and Goossens-Fontana 505a & 505b. Goossens-Fontana 505a is designated as lectotype (Verbeken 1996a). The specimens are in rather good condition and agree perfectly with the more recent collected material from Democratic Republic of Congo and Zambia.

     The macroscopic description is based on the field notes of Goossens-Fontana, Buyck and Verbeken. The microscopic description is based on Goossens-Fontana 143a & 505a, Buyck 3471 and A. Verbeken 94-082.

     In the field this species can very easily be confused with Lactarius laevigatus. It differs mainly by the presence of thick-walled hair-like elements in the pileipellis. The species differs from Lactarius chamaeleontinus by its firmer and bigger habit and its smaller spores.

 

10. Lactarius laevigatus  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 203 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 31 March 1994, A. Verbeken 94-535 (BR 57694–76, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 155–156 & Pl. 104–106 (1996d); Karhula & al., Karstenia 38: fig. 19 (1998).

 

Pileus 10–70 mm, thick, but brittle, infundibuliform; margin deflexed upwards, strongly striate to sulcate; pellis not dehiscent, smooth, wet, not viscose, finely fibrous in the centre, light orange to greyish orange (4A5 to 5AB5), locally more yellow, darker when older. Lamellae decurrent, unequal with mostly 1 lamellula between 2 lamellae, rather distant (L+l = 2+2 to 3+4/cm), rather thick, broad (7 mm), very brittle, with numerous small veins, sometimes anastomosing, pale yellow (3A3); edge entire, concolorous. Stipe 40–50 × 10–20 mm, cylindrical, tapering towards the base, dry, wrinkling towards the apex and the base, pale yellow (4A3), solid but brittle. Context white to cream; taste mild, then acrid; smell not particular. Latex scarce, white. Spore-deposit white. – Pl. 7

 

Chemical reactions. Context unchanging or greyish to greenish with FeSO4, faintly greenish blue with gaiac, unchanging with NH4OH. Pileipellis olive-yellow with KOH.

 

Basidiospores ellipsoid, 7.9–8.99.3–9.9(–10.2) × 6.4–7.27.3–7.9 mm (n = 80, Q = 1.15–1.231.28–1.37); ornamentation amyloid, composed of irregularly shaped and sized warts, aligned or connected by fine connective lines, never forming a reticulum, very low, not exceeding 0.2 mm height; plage sometimes with a faintly amyloid spot in the centre. Basidia (40–)50–60 × 9–12 mm, subclavate to clavate, 4-spored. Pleurocystidia absent. Pleuropseudocystidia rather abundant, 10–17 mm diam., cylindrical to fusiform, sometimes mucronate, emergent up to 50 mm; content densely oleiferic and needle-like. Lamellar edge sterile; marginal cells 20–40 × 4–7 mm, cylindrical, with rounded apex, slender, sometimes branched. Hymenophoral trama composed of sphaerocytes and scarce lactifers, with narrow, hyaline hyphae towards the edge. Pileipellis ixocutis-like to trichoderm-like, with recumbent and locally ascending chains of short cylindrical elements, 20–30(–40) × 5–10 mm, thin-walled or very slightly thick-walled; terminal elements rounded, sometimes mucronate, remarkably dark and band-wise coloured in cresyl-blue. Stipitipellis cutis to ixocutis, composed of narrow, thin-walled hyphae, 2–10 mm diam., often septate. Clamp-connections absent. – Fig. 34

 

Ecology. Zambezian miombo woodland. Collected under Caesalpiniaceae and Uapaca spp.

 

Distribution. Known from Burundi, Malawi, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Burundi. Bururi Prov., Rumonge Forest Reserve, Nyamirambo, May 1993, B. Buyck 5138 (PC); Ibid., March 1994, A. Verbeken 94-082b (BR 57593–72), 94-163 (BR 57616–95) & 94-535 (BR 57694–76, holotype; GENT, isotype); Ibid., 1 April 1994, A. Verbeken 94-579 (BR 57706–88); Nkayamba, just N of Rumonge, 11 Dec. 1992, B. Buyck 4737 (PC); Mugara, 29 Nov.1978, J. Rammeloo 5932 (BR 8775–45).

Malawi. Southern Prov., Blantyre, ± 1000 m, Dec. 1971, Williamson 536 (K(M) 38473).

Zambia. Copperbelt Prov., Chati‑forest, near Kitwe, Dec. 1990, B. Buyck 3117-3121, 3123-3125, 3185, 3207 & 3211 (all PC).

Zimbabwe. Mashonaland East Prov., Liemba farm, 2 Feb. 1999, A. Verbeken 99-079 & 99-080 (all GENT); Midlands Prov., Mvuma, Central Estates, paddock 77, 5 Feb. 1999, A. Verbeken 99-127 & 99-129 (all GENT); Masvingo Prov., south of Lake Mutirikwe, around Norma Jean’s lodge, 16 Feb. 1999, A. Verbeken 99-223 (GENT).

 

Notes. On a young basidiome of Buyck 3211, an indusium (referred to as "cortina" in the fieldnotes) is observed. It becomes a fugitive and very thin annulus near the apex of the stipe, which disappears later.

     Both species, Lactarius sesemotani and L. laevigatus are recognized by the striate or sulcate and shiny pileus, even in the exsiccata. Lactarius laevigatus differs from L. sesemotani by the lack of thick-walled and hair-shaped elements in the pileipellis, but resembles the species in every other character. This difference is not correlated with the state of development (thick-walled hairs disappearing with age), since both species are studied in both young and old condition.

     This species is locally consumed, e.g. in Tanzania (Karhula & al. 1998).

 

11. Lactarius pruinatus  Verbeken & Buyck

Verbeken, Mycotaxon 66: 399 (1998). Type: Zambia, Copperbelt, Chati-forest near Kitwe, 24 Dec. 1990, B. Buyck 3248 (GENT, holotype; PC, isotype).

 

Selected descriptions and icons. Verbeken, Mycotaxon 66: 399–403 (1998).

 

Pileus 17–25 mm diam., almost applanate, slightly depressed in the centre, with central papilla; margin straight, not really striate but radially wrinkled when drying; pellis mat, dry, pruinose, with very short hairs, yellowish brown to pale brown (4AB6 to 5C4–6). Stipe 18–25 × 5–10 mm, strongly flattened, with irregular folds and a bit tortuous, fragile and completely hollow; pellis velvety, with short hairs, white to cream, pure white at the base. Lamellae clearly decurrent, moderately distant, with lamellulae, cream (3A2–3); edge entire, concolorous. Context white to cream, unchanging; taste very acrid. Latex white, unchanging or a bit watery; taste very acrid. Spore-deposit white. – Pl. 8

 

Chemical reactions. Context unchanging to pale greyish with FeSO4.

 

Basidiospores subglobose to ellipsoid, 8.4–9.8–11 × 7.4–8.2–9.0 mm (n = 20, Q = 1.07–1.19–1.30); ornamentation amyloid, very regularly reticulate, composed of ridges, up to 0.5(–1) mm high, forming an almost complete to complete reticulum; wall clearly and typically rugose between the meshes; plage not amyloid. Basidia 4-spored, seldom 2-spored, 55–65 × 12–14 mm, subclavate; sterigmata 8–10 × 2–3 mm. Pleurocystidia absent. Pleuropseudocystidia not very abundant, mostly emergent up to 35 mm, 7–18 mm broad, fusiform, sometimes with moniliform apex, thin-walled or with slightly refringent walls; content slightly needle-like. Lamellar edge sterile: marginal cells cylindric or fusiform, 17–40 × 2–7 mm, thin-walled, hyaline. Hymenophoral trama composed of sphaerocytes mainly; some hyaline hyphae and lactifers present. Subhymenium cellular. Pileipellis a lamprotrichoderm; elements of the suprapellis cylindric to subcylindric, with obtuse or more or less acute apex, 20–50(–70) × 4–7 mm, thick-walled and sometimes septate; subpellis composed of hyaline hyphae. Stipitipellis a lamprotrichoderm; elements of the suprapellis cylindric to subcylindric, with obtuse or more or less acute apex, sometimes branched, 20–80 × 3–10 mm, thick-walled and sometimes septate; subpellis composed of hyaline hyphae. Clamp-connections absent. – Fig. 35

 

Ecology. Found in wetter Zambezian miombo woodland.

 

Distribution. Only known from type locality.

 

Revised specimens

Zambia. Copperbelt Prov., near Kitwe, Chati-forest, 24 Dec. 1990, B. Buyck 3248 (GENT, holotype; PC, isotype).

 

12. Lactarius uapacae Verbeken & Stubbe

Verbeken & al., Cryptog. Mycol. 29: 140 (2008). − Type: Cameroon, forêt de Dja, 30 Jan. 1993, A. Verbeken 07- 48 (GENT, holotype).

 

Selected descriptions and icons. Verbeken & al., Cryptog. Mycol. 29: 140-142 (2008).

 

Pileus 10–14 mm diam., applanate with slight depression or slightly curved upwards in the centre; surface transparently striate-grooved, minutely felty, opaque, slightly greasy, lacking veins, very pale yellow to yellowish white (4A3) at the margin and when older, in centre and in young specimens slightly darker buff-yellowish to pinkish buff. Lamellae broadly adnate, distant, with 3 lamellulae between 2 lamellae, with regular short-long-short pattern, yellowish white; edge entire, concolorous. Stipe 7–10 × 1–3 mm, subcyindrical or strongly curved, tapering downwards, sometimes irregular, pale buff to whitish. Context very thin-fleshed, hollow in stipe, dirty pale yellow, unchanging; smell not remarkable; taste unknown. Latex not observed. – Pl. 8

 

Spores subglobose to broadly ellipsoid, 8.5–9.9–11.4 × 7.8–8.9–9.9 µm (Q = 1.05–1.12–1.22, n = 20); ornamentation amyloid, subreticulate, composed of wings up to 1(1.5) µm high; plage not amyloid. Basidia 35–45 × 12–15 µm, (2) 4-spored, clavate. Pleurocystidia absent. Pseudopleurocystidia abundant, very emergent, locally up to 20 µm diam., fusiform or irregular, sometimes branching. Lamellar edge sterile; marginal cells 20–37 × 4–6 µm, subfusiform to subcylindrical, thin-walled, hyaline. Hymenophoral trama cellular, composed of rather large sphaerocytes and lactifers. Pileipellis a lampropalisade, 60–80 µm thick; terminal elements subfusiform to subcylindrical, 15–35 × 6–9 µm, thick-walled; subpellis 40–50 µm thick. Stipitipellis a lamprotrichopalisade to lamprotrichoderm; terminal elements longer and more variable than in the pileus. – Fig. 36

 

Ecology. Guineo-Congolian rainforest. Found on branchlets under Uapaca.

 

Distribution. Only known from the type locality.

 

Revised specimens

Cameroon. Eastern Prov., Réserve de faune du Dja, campement dans la brousse, 10 April 2007, A. Verbeken 07-48 (GENT, holotype).

 

Notes. Striking characteristics for this species are the pale yellow and small basidiocarps. Microscopically the species is characterized by the large spores with subreticulate ornamentation. The broad and emergent pseudocystidia are typical for representatives of Lactarius sect. Chamaeleontini Verbeken, as are the yellowish colours and the sulcate pileus. The species differs from all other members of this section by its small basidiocarps and the pure lampropalisade.

 

13. Lactarius emergens Verbeken

Verbeken & al., Syst. Geogr. Pl. 70: 192 (2000). − Type: Zimbabwe, Mvuma, Central Estates, Beacon Hill section, 26 Jan. 1999, A. Verbeken 99-006 (GENT, holotype).

 

Selected descriptions and icons. Verbeken & al., Syst. Geogr. Pl. 70: 192–194 (2000).

 

Pileus 40–80 mm diam., convex to planoconvex and slightly depressed, a bit irregular; pellis smooth, glabrous, radially subfibrillose, rather sticky, yellowish white to light yellow (4A2–5), darkest in the center, paler outside; margin first smooth, strongly striate, grooved in older specimens (up to 10 mm from margin). Lamellae slightly decurrent, very distant (L+l = 7–9/cm at midradius in young basidiomes, L+l = 4/cm in older ones), rather thick, brittle, anastomosing at some places, yellowish white (3A2 to 4A4); edge slightly darker. Stipe 30–50 × 12–17 mm, more or less cylindric, a bit curved and irregular; pellis smooth, glabrous, white, becoming pale greyish. Context rather thick but thin near margin, with 2 chambers in stipe, white to cream, unchanging; smell agreeable, reminding of Russula fellea; taste acrid, but disappearing soon. Latex very scarce, white, unchanging, unchanging with KOH. Spore-deposit not observed. – Pl. 9

 

Chemical reactions. Context very faint blueish grey with gaiac, unchanging with FeSO4.

 

Basidiospores subglobose to ellipsoid, 7.0–8.0–9.0–9.9 × 6.0–6.6–6.7–7.3 µm (Q = 1.08–1.21–1.33–1.43, n = 40); ornamentation amyloid, extremely weakly developed, composed of low warts (less than 0.2 µm high) and some ridges; plage not amyloid. Basidia 50–65 × 9–11 µm, 4-spored, subclavate, with guttate content; sterigmata very short (up to 5(7) µm) and thick (up to 3 µm). Pleurocystidia absent. Pleuropseudocystidia rather abundant, sometimes emergent, up to 10(12) µm diam., tortuous, subcylindric, with tapering apex, with needle-like content. Hymenophoral trama cellular and with abundant lactifers. Lamellar edge sterile; marginal cells subcylindric, subfusiform, 15–25 × 6–9 µm, thin-walled, hyaline. Pileipellis trichopalisade-like, with abundant thick-walled elements, which are long, cylindric, with rounded but tapering apex, 40–90 × 4–6 µm, often septate; some swollen to subglobose elements present; diverticulate knobs present on some terminal elements and some hyphae. Stipitipellis a trichoderm, composed of thin-walled hyphae where some knobs are present. Clamp-connections absent. – Fig. 37

 

Ecology. Found in drier Zambezian Brachystegia woodland and under Uapaca in Isoberlinia woodland.

 

Distribution. Known from Benin and Zimbabwe.

 

Revised specimens

Benin. Borgou Prov., Wari Maro, 19 June 2000, A. De Kesel 2834 (BR 126387–93).

Zimbabwe. Midlands Prov., Mvuma, Lovedale Ranch, Beacon Hill section, at the ostrich incubator, on the ridge, 26 Jan. 1999, A. Verbeken 99-005 (GENT), 99-006 (GENT, holotype) & 99-012 (GENT).

 

Notes. The species is closely related to Lactarius sesemotani (Beeli) Buyck (Lactarius section Chamaeleontini Verbeken) from which it differs macroscopically by the paler and more whitish colours and the chambered stipe. Microscopically the thick-walled hairs in the pileipellis of L. sesemotani are more pronounced (walls 1 µm thick) and longer. Diverticulate knobs have never been observed in the pileipellis-elements of L. sesemotani. Pleuropseudocystidia are more abundant in Lactarius emergens and less emerging as in L. sesemotani. The basidia are clearly larger in L. emergens (35–40 × 8–10 µm in L. sesemotani) and the spores have never been observed to have an amyloid spot on the plage as in L. sesemotani.

Lactarius emergens emerges typically under the soil and pushes the soil upwards when growing mature. Much soil remnants remain on the rather sticky cap.

 

14. Lactarius brachystegiae Verbeken & C. Sharp

Verbeken & al., Syst. Geogr. Pl. 70: 187 (2000). – Type: Zimbabwe, Mvuma, Central Estates, Beacon Hill, 26 Jan. 1999, A. Verbeken 99-002 (GENT, holotype).

 

Selected descriptions and icons. Verbeken & al., Syst. Geogr. Pl. 70: 187–190 (2000); Verbeken, Micol. Veget. Medit. 16: fig. 3 (2001).

 

Pileus 32–110 mm diam., first convex, undeeply depressed and with strongly recurved margin, then becoming more planoconvex and with a deeper depression, finally infundibuliform and with an irregular, wavy margin; margin straight in older specimens, grooved, striate in older specimens (up to 20 mm long); pellis especially in young specimens soft, pruinose, almost velvety and in center sometimes very finely cracked, but towards margin and also when older smooth, glabrous, a bit sticky (leave remnants sticking on the pileus) and radially fibrillose, never really wet, golden yellow-orange to deep orange (5AB6–7 to 5A8), light yellow to reddish yellow (4A5–6) near margin, light brown to reddish brown (6D7 to 8D8) in center, when rottening dark reddish brown from margin on. Lamellae broadly adnate to shortly decurrent, rather spaced (L+l = 6–7/cm halfway), with a lot of short lamellulae, anastomosing and furcated lamellae present, 3–6 mm broad, rather thick, brittle, pale orange to orange white (5A2–3); edge staining a bit darker. Stipe 10–35 × 10–22 mm, relatively short, cylindrical, in some specimens distinctly broader at the base, in others distinctly narrower (like a triangle); pellis smooth, soft, glabrous, with very fine, darker, vertical lines (like varicose veins), pale yellow to pale orange (4A2–3 to 5A2–3), some with darker spots (but no scrobicules), some with a whitish zone at the extreme base and some with a slightly darker narrow zone at the extreme top. Context thick and firm, up to 4 mm in pileus, solid, hard and robust in stipe (sometimes soft because of damage by insects), white to very pale orange, especially under the pileipellis, pale, whitish to cream in the stipe, a bit more flesh-coloured after a while, smell apple-like, strongly sweetish, like Russula fellea, Lactarius evosmus; taste first mild, soon acrid and slightly astringent, burning, but disappearing soon. Latex very scarce to rather abundant, watery white, unchanging (Verbeken 99-004) or golden yellow (Verbeken 99-132) with KOH; taste as context. Spore-deposit not observed. – Pl. 10

 

Chemical reactions. Context bright blue after some minutes with gaiac, very slightly salmon or unchanging with FeSO4.

 

Basidiospores broadly ellipsoid to ellispoid, 9.5–10.510.6–11.5 × 7.6–8.28.4–9.0 µm (Q = 1.15–1.261.28–1.38, n = 40); ornamentation amyloid, composed of irregular, more or less rounded warts, sometimes aligned, sometimes connected by fine lines, about 0.5 µm high; plage not amyloid. Basidia 65–75 × 10–12 µm, subcylindric to subclavate, 4-spored; sterigmata 5–8 × 2–4 µm. Pleurocystidia absent. Pleuropseudocystidia abundant, emergent up to 40 µm above the hymenium, up to 18 µm broad, fusiform to clavate but with tapering or capitate apex; content needle-like. Hymenophoral trama cellular, with abundant lactifers. Lamellar edge sterile, composed of marginal cells; marginal cells 13–30 × 6–10 µm; irregularly cylindric to subclavate, thin-walled, hyaline. Pileipellis (ixo)cutis-like but with abundant swollen compartiments; terminal elements mostly pericline and usually cylindric, sometimes clavate or irregular, 20–50 × 5–8 µm; some slightly thick-walled elements present; pseudocystidia present, 8–10 µm diam., with needle-like content, capitate; diverticulate knobs or bulges present on both terminal elements and hyphae of the subjacent layer. Stipitipellis a trichoderm; terminal elements mostly anticline, thin-walled, cylindric to subclavate, 12–40 × 5–7 µm, with diverticulate knobs. Clamp-connections absent. – Fig. 38

 

Ecology. Associated with Brachystegia species (e.g. B. glaucescens, B. spiciformis) in Zambezian miombo woodland. In central Zimbabwe Lactarius brachystegiae seems a common species. It was mostly observed in well-developed Brachystegia leaf litter, especially under Brachystegia glaucescens on hills.

 

Distribution. Known from Malawi, Tanzania and Zimbabwe.

 

Revised specimens

Malawi. Southern Prov., Makwawa, Zomba, 7 Jan. 1991, B. Morris 91-23 (PC); Ibid., 9 April 1994, B. Buyck 3978-3981 (all PC).

Tanzania. Southern Highlands Prov., Mbeya distr., Ipembe Hill, 28 March 1991, T. Saarimäki & al. 747 (H, judging from photograph in unpublished thesis of Karhula 1997: 62).

Zimbabwe. Midlands Prov., Mvuma, Central Estates, Beacon Hill Homestead, garden Sharp, 26 Jan. 1999, A. Verbeken 99-002 (GENT, holotype); Ibid., 4 Jan. 1997, C. Sharp 518/97 (GENT); Central Estates, Beacon hill section, at the ostrich incubator, 26 Jan. 1999, A. Verbeken 99-004 (GENT); Ibid., 9 Jan. 1997, C. Sharp 539/97 (GENT); Midlands Prov., Mvuma, Central Estates, along road north of the ostrich incubator, leg. R. Walleyn 6 Feb. 1999, A. Verbeken 99-132 (GENT).

 

Notes. The description is based on the collections from Zimbabwe.

     This species is included here in Lactarius sect. Chamaeleontini but the characters of the pileipellis are more reminescent of species of L. sect. Russulopsideae. 


Sect. Russulopsidei  Verbeken

 

Lactarius sect. Russulopsidei Verbeken, Mycotaxon 77: 441 (2001).

Type species: Lactarius ruvubuensis Verbeken.

 

Key to tropical African species

 

1.  Hymenophoral trama mainly composed of sphaerocytes .................................................................. 2

     Hymenophoral trama irregular to regular, mainly composed of hyaline, more or less parallel hyphae, occasionally with a few sphaerocytes .......................  6

 

2.  Spore-ornamentation composed of conical, pointed to slightly rounded spines, up to 1.5 mm high, connected by fine connective lines, forming an almost complete reticulum ...  22. L. corbula

     Spore-ornamentation composed of irregular, rounded and obtuse warts, isolated or connected by fine connective lines .....  3

 

3.  Lamellar edge reddish brown ...........................................................................  19. L. rufomarginatus

     Lamellar edge concolorous .....................................................  4

 

4.  Taste mild; elements of the pileipellis without remarkable bulges .....  20. L. pseudotorminosus

     Taste very acrid; elements of the pileipellis with remarkable diverticulate bulges ........................  5

 

5.  Stipe shortly cylindrical; lamellae rather distant (3+7 to 4+8/cm); pileus becoming greyish dark brown from the margin to the centre when old and rottened; latex unchanging; pleurocystidia mostly present and abundant .......  15. L. ruvubuensis

     Stipe long and slender; lamellae very crowded (22–32/cm); pileus becoming paler when older; latex sometimes greyish to blackish when drying; pleurocystidia absent ......  16. L. longipes

 

6. Latex blue-greenish when drying; spores very lowly ornamented; pileus unicolorous .......... 17. L. cyanovirescens

     Latex unchanging when drying; spore-ornamentation 0.2–0.5 mm high; pileus clearly darker in the centre and paler towards the margin ................. 7

 

7.  Pileipellis with clearly moniliform dermatocystidia; lamellae crowded and narrow (2–2.5 mm); taste of latex slightly acrid ...............................................................................................  21. L. claricolor

     Some of the elements of the pileipellis with lactiferous content and reminding dermatocystidia; lamellae rather distant and broader (3–13 mm); taste of latex burning acrid ......  18. L. urens

 

Species descriptions

 

15. Lactarius ruvubuensis  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 208 (1996). − Type: Burundi, Ruvubu National Park, 6 Apr. 1994, A. Verbeken 94-599 (BR 57708–90, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 207208 & Pl. 208215 (1996d).

 

Pileus (40–)55–90 mm diam., quite thick, slightly to deeply infundibuliform; margin incurved to deflexed downwards when young, then straight and deflexed upwards, striate when older; pellis dehiscent at the margin, dry, finely tomentose in the centre, finely fibrose towards the margin, light brown in the centre (5D5–6), brownish orange to reddish towards the margin (6C4–6), becoming greyish dark brown from the margin to the centre when old and rottened. Lamel­lae strongly decurrent, unequal with lamellulae between 2 lamellae (1–3, irregular pattern), dichotomous near the margin, quite distant (L+l = 3+7 to 4+8/cm), thick, medium broad (3–8 mm), brittle, sometimes with finely anastomosing veins, white; edge entire, concolorous. Stipe (20–)35–45 × 6–22 mm, short, tapering downwards, dry, smooth, reddish brown to brownish orange, broadly fistulous. Context firm in pileus, brittle in stipe, white, changing greyish brown when rottening; taste faint mild to bitter, then acrid; smell apple-like, sweet, unpleasantly sweet when older. Latex abundant, fluid, white, unchanging; taste very acrid. Spore-depo­sit white. – Pl. 11

 

Chemical reactions. Context salmon, light orange with FeSO4. Pileipellis red with KOH.

 

Basidiospores subglobose to ellipsoid, 7.1–7.98.1–8.7(–8.9) × 6.3–6.87.0–7.6 mm (Q = 1.07–1.131.17–1.27; n = 80); ornamentation amyloid, composed of irregular warts and connective lines, never forming a reticulum, some warts isolated, up to 0.3 mm high; plage inamyloid. Basidia 45–60 × 9–10 mm, slightly clavate, 4-spored. Pleurocystidia scarce to abundant, 35–50 × 3–5 mm, tortuous to irregularly branched and diverticulate. Pleuropseudocystidia scarce to abundant, 3–5 mm diam., tortuous to irregularly branched and diverticulate. Lamellar edge sterile; marginal cells 25–35(–45) × 3–6 mm, irregularly clavate to tortuous, often diverticulate and branched at the apex. Hymenophoral trama composed of isodiametric cells; lactifers scarce to rather abundant, in some specimens even absent. Pileipellis a cutis, composed of hyaline hyphae, often septate, 3–7 mm diam., with diverticulate bulges; lactifers present; dermatocystidia present, capitate, 35–45 × 4–6 mm, with needle-like content (dark-brown pigmentation in upper layer). Stipitipel­lis a trichoderm; terminal elements fusiform; at the base of the stipe consisting of slender, often dichotomously branched, slightly thick-walled hyphae. Clamp-connections absent. – Fig. 39

 

Ecology. Found in damp forest, under Uapaca guineensis.

 

Distribution. Only known from Burundi and Guinea.

 

Revised specimens

Burundi. Ruyigi Prov., Ruvubu National Park, April 1994, A. Verbeken 94-598 (BR 57707–89), 94-599 (BR 57708–90, holotype; GENT, isotype), 94-600 (BR 57709–91), 94-601(BR 57710–92) & 94-617 (BR 57711–93).

Guinea. Forêt humide de Ziama, 31 July 2000, A. Bâ 185 (GENT); Ibid., 1 Aug. 2000, A. Bâ 305 (GENT).

 

Notes. Both macroscopic and microscopic descriptions are based on the collections from Burundi.

In some specimens (e.g. Verbeken 94-599 & 94-617) lactifers in the trama are rather abundant and pleuropseudocystidia are also rather abundant, while true pleurocystidia are scarce. In other specimens (e.g. Verbeken 94-600) lactifers and pseudocystida could not be observed in the trama of the lamella, which makes the trama look exactly like that of a Russula species. There was latex observed in fresh condition, and there are lactifers in the trama of the pileus. The true pleurocystidia become more abundant as the pseudocystidia are absent. Those true cystidia have exactly the same size and shape as the pseudocystidia in the other specimens. They are not connected with lactiferous hyphae, although they arise rather deep in the hymenium.

 

16. Lactarius longipes  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 203 (1996). − Type: Democratic Republic of Congo, Kivu, Irangi, 6 April 1972, J. Rammeloo Z242 (GENT, holotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 208209 & Pl. 215217 (1996d).

 

Pileus 30–60 mm diam., firm, moderately thick, regular, slightly depressed to infundibuliform; margin sharp, involute when young, slightly striate and irregularly undulate when old; pellis adnate, not dehiscent, mat, almost smooth, slightly concentrically zonate, radially wrinkled, not unicolorous, with darker and brighter spots of reddish golden and brownish orange (6C8), light brown (6D6–8), dark brown (6F6–8) or darker in the centre and paler towards the margin, greyish orange to reddish blond (5BC6) when older. Lamellae adnate to subdecurrent, unequal with numerous lamellulae of different lengths, frequently forked, very dense (22–32/cm), very narrow (1–1.5 mm), thin, greasy, pale yellow (1A3) to yellowish white (3A2–3) when young, orange white (5A3) when older; edge entire, concolorous. Stipe 35–80 × 6–15 mm, cylindrical, long and slender, sometimes tapering downwards, slightly longitudinally grooved, light brown to brown in upper part (6DE8), brownish orange to reddish golden in lower part (6C5–6), whitish near the base, firm, solid. Context firm, white, yellowish to ochraceous under the pellis, unchanging; smell sickly or sweetish, particular; taste very acrid. Latex abundant, white, becoming transparent, sometimes greyish to blackish when drying; taste very acrid. Spore-deposit cream to pale yellowish (not observed in fresh condition). – Pl. 12

 

Chemical reactions on context. Anilated H2O: pale ochraceous, pale brown to brown after a while. Phenol, TL4 NH4OH: nihil.

 

Basidiospores subglobose to ellipsoid, 6.7–7.57.9–8.8 × 5.0–6.56.6–7.3 mm (Q = 1.06–1.141.15–1.24, n = 60); ornamentation amyloid, composed of irregular warts, isolated or connected by fine connective lines, up to 0.5 mm high; plage inamyloid or with slightly amyloid spot. Basidia 35–45 × 7–10 mm, cylindrical to narrowly clavate, 4-spored, seldom 2-spored. Pleurocystidia absent. Pleuropseudocystidia abundant, emergent, 4–5(–7) mm diam., cylindrical and tortuous, often branched and with bulges; content oleiferic to needle-like. Lamellar edge sterile; marginal cells 15–30 × 4–6(–7) mm, cylindrical, tortuous, sometimes septate, hyaline, thin-walled. Hymenophoral trama composed of sphaerocytes; narrow, hyaline hyphae near the edge; lactifers abundant. Pileipellis a cutis, composed of hyaline hyphae, often septate, 3–7 mm diam., sometimes tortuous or with some bulges; lactifers present, penetrating in the upper layer; dermatocystidia very abundant, capitate or subcapitate, (25–)30–45 × 4–6 mm, with needle-like content. Stipitipellis idem as pileipellis; abundant caulocystidia. Clamp-connections absent. – Fig. 40

 

Ecology. Found in Guineo‑Congolian rainforest with Gilbertiodendron dewevrei and Scaphopetalum thonneri, and riverine forest with Uapaca guineensis.

 

Distribution. Known from the Democratic Republic of Congo, Togo and Gabon.

 

Revised specimens

Democratic Republic of Congo. Tshopo Prov., 5 km NNE of Batiabongena, April 1984, B. Buyck 1336 (BR 8766–36); Ibid., B. Buyck 1345 (BR 12745–38); Ibid., B. Buyck 1346 (BR 12746–39); Kivu Prov., Irangi, March 1972, J. Rammeloo Z228 (GENT); Ibid., April 1972, J. Rammeloo Z242 (GENT, holotype); Ibid., June 1972, J. Rammeloo Z271 (GENT).

Gabon. Research Station of Ipassa-Makokou, border of Ivindo river, 21 March 2005, J. Degreef 303 (BR 164551–39); Research Station of Ipassa-Makokou, 25 March 2005, M. Nguele 29 (BR 164545–33).

Togo. Central Prov., Forêt Classée de Alédjo, Gallery forest with Berlinia grandiflora, Uapaca guineensis, Pentadesma and Breonadia, 12 July 2007, A. Dekesel 4315 (BR 163825–89).

 

Notes. The type consists of 5 basidiomes in good condition.

     The species reminds Lactarius claricolor by the habit and the dermatocystidia, differs however because of the darker colour of the pileus and the stipe, the very acrid taste, the heteromerous trama (subregular in L. claricolor) and the spore ornamentation (which looks more pronounced in L. kivuensis, but was more difficult to observe in L. claricolor, due to the alcohol-conservation).

     The species is closely related to Lactarius ruvubuensis. They are microscopically almost identical, especially with regard to the abundant pileocystidia and the very remarkable shape of the pleurocystidia. However in Lactarius longipes, the pleurocystidia are never true cystidia, only pseudocystidia, and the bulges and diverticulate elements in the pileipellis are scarce, whereas they are very abundant in L. ruvubuensis. These differences, combined with the more striking difference in number and spacing of the lamellae, make the two taxa specifically different.

     According to Rammeloo (herbarium notes), this species is locally eaten in the Democratic Republic of Congo.

 

17. Lactarius cyanovirescens Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 199 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 11 March 1994, A. Verbeken 94-080 (BR 57590–69, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 214215 & Pl. 233237 (1996d).

 

Pileus 65–95 mm diam., firm, fleshy, convex to planoconvex and depressed in the centre to slightly infundibuliform; margin incurved, then straight and irregularly crenulate, faintly striate or sulcate; pellis not or slightly dehiscent, smooth, dry to very slightly sticky, mat, brownish orange to light brown (6D7), greyish red (7C3 to 7D4 or 8CD4), dull red (8B3–4), locally or in the centre paler (3AB3). Lamellae adnate to subdecurrent, unequal with lamellulae of different lengths (1–3 lamellulae between two lamellae), exceptionally forked, distant (L+l = 2+1, 3+8 to 4+4/cm), moderately broad to broad (4–9 mm), thick, brittle, sometimes with venation towards the margin of the pileus, white to cream, pale yellow (3A3) or pale brownish yellow (4A4), staining blue-green to greyish green by the latex; edge entire, concolorous. Stipe 25–40 × 8–20 mm, shortly cylindrical, tapering downwards, smooth, pale yellow (4A4–5), pale orange, orange to reddish brown (6CD5), whitish near the apex, with a whitish felty layer at the base, soon chambered. Context firm, 4–7 mm in pileus, white, staining blue-green by latex-contact; taste mild; smell sometimes agreeable, sometimes slightly H2S-like. Latex scarce to rather abundant, white, blue-green (25C4–7) when drying; taste spicy to very acrid. Spore-deposit white to pale cream. – Pl. 12

 

Chemical reactions. Context slowly salmon red with FeSO4. Pileipellis pale yellowish green with KOH.

 

Basidiospores ellipsoid, 7.3–8.28.6–9.4 × 6.3–6.97.2–8.2 mm (Q = 1.04–1.161.23–1.33, n = 100); ornamentation not very distinct, very low and irregular, composed of some irregularly shaped and sized warts, often aligned or connected by connective lines; plage inamyloid. Basidia 40–55 × 9–10(–11) mm, cylindrical to subclavate, 4-spored; content guttate. Pleurocystidia absent. Pleuropseudocystidia rather abundant, emergent, cylindrical, with rounded apex; content needle-like. Lamellar edge sterile; marginal cells 25–55 × 4–7(–10) mm, tortuous, with bulges, sometimes branched, often septate, thin-walled, hyaline. Hymenophoral trama heteromerous, composed of sphaerocytes, a few hyaline, thin-walled hyphae and abundant lactifers. Pileipellis a cutis, composed of a layer of interwoven, more or less parallel hyphae, thin-walled, hyaline, septate, 3–5 mm diam, locally swollen up to 15 mm; pileocystidia scarce, 20–30 × 3–5 mm, with very dense oleiferic yellowish brown content. Stipitipellis trichoderm-like to subcellular with hymeniform aspect, composed of a few isodiametric to more elongated cells, mostly forming chains; terminal elements 15–35 × 2–5(–7) mm, cylindrical, slender, thin-walled; base of the stipe covered with long and slender hyphae, 3–5(–8) mm diam. Clamp-connections absent. – Fig. 41

 

Ecology. Miombo woodland, dry evergreen forest (muhulu), often under Brachystegia spp.

 

Distribution. Known from Burundi, Democratic Republic of Congo, Malawi, Tanzania and Zambia.

 

Revised specimens

Burundi. Bururi Prov., Rumonge Forest Reserve, Nyamirambo, Nov. 1993, B. Buyck 5191 & 5225 (all PC); Ibid., March 1994, A. Verbeken 94-080 (BR 57590–69, holotype; GENT, isotype), 94-300 (BR 57642–24), 94-514 (BR 57684–66), 94-515 (BR 57685–67) & 94-516 (BR 57686–68); Ibid., Nkayamba, near Rumonge, Dec. 1991, B. Buyck 4045 & 4046 (all PC); Ibid., Jan. 1992, B. Buyck 4174 (PC); Ibid., April 1992, B. Buyck 4379 & 4428 (all PC); Ibid., March 1993, B. Buyck 4984, 4989 & 4999 (all PC); Ibid., April 1994, A. Verbeken 94-151 (BR 57605–84), 94-152 (BR 57606–85) & 94-164 (BR 57617–96); Cankuzo Prov., Murango, Dec. 1994, B. Buyck 5665 (PC).

Democratic Republic of Congo. Shaba Prov., Kipopo, 5 Dec. 1971, D. Thoen 5089 (BR 66274–23); Shaba Prov., Lubumbashi, Feb. 1986, J. Schreurs 1055 (BR 7896–39); Shaba Prov., Luiswishi, 14 Dec. 1971, D. Thoen 5127 (BR 66281–30).

Malawi. Northern Prov., Mzimba distr., Mtanga tanga forest, 15 March 2005, F. Noe 05/562-565 & 05/567 (all GENT); Ibid., 16 March 2005, F. Noe 05/629-633 (all GENT); Perekezi Forest Reserve, 9 March 2005, F. Noe 05/454 & 05/466 (all GENT); Ibid., 16 March 2005, F. Noe 05/634 (GENT).

Zambia. Northern Prov., Mpika distr., North Luangwa National Park, Mwaleshi Camp, 10 Feb. 1995, D. Shah‑Smith 214 (K(M) 35512); Mbereshi National Forest, NF 265, 22 Feb. 1998, herb. M. Groenendaal L2; farm Gibsons, 19 Jan. 1996, B. Buyck & G. Eyssartier 96-124 (PC); Lake Kashyba, 24 Jan. 1996, B. Buyck & G. Eyssartier 96-167 (PC).

 

Notes. The macroscopic description is based on fieldnotes from Verbeken, Buyck and Schreurs; the microscopic description is especially based on Verbeken 94-080 & 94-151, Schreurs 1055 and Buyck 4045.

     The taste of the context was noted to be acrid in Schreurs 1055.

 

18. Lactarius urens  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 211 (1996). – Type: Burundi, Mugara, 2 Dec. 1978, J. Rammeloo 6002 (BR 18874–56, holotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 211213 & Pl. 223229 (1996d); Verbeken & al., Syst. Geogr. Pl. 70: 208211 (2000).

 

Pileus 40–120(–150) mm diam., firm, medium thick, convex to planoconvex, with a depressed centre to infundibuliform when older; margin involute to incurved when young, then waving and irregularly crenulate, broadly and longly striate when old; pellis dehiscent up to halfway the radius, finely felty, with very small squamules, smooth to even shiny when old, with remarkable difference in colour between the centre and the margin, brownish orange to light brown (6CD5–7) in the centre, greyish orange (5CD7), golden yellow (5B4–6), buff to cream (3A2) in the outer zone, with remaining reddish brown squamules. Lamellae adnate when young, decurrent when older, unequal with lamellulae of different lengths (1–3 lamellulae between two lamellae, if three then regular short-long-short pattern), moderately distant to distant (L+l = 2+2 to 5+5/cm), moderately broad to broad [(3–)5–10(–13) mm)], rather thick, firm to brittle, sometimes with venation, seldom dichotomously branched towards the apex of the stipe, cream to pale yellow; edge entire, concolorous. Stipe (20–)30–55 × 8–20(–25) mm, shortly cylindrical, tapering downwards, finely felty to smooth, slightly wrinkling, brownish orange when young (6C3–4 to 6D4–5), greyish orange (5A3 to 5B4) when old, paler at the apex, solid, firm. Context firm, white, changing to cream (4A2) when cut; smell agreeable and fruit-like to unagreeable and slightly chemical; taste mild and nut-like in the stipe, often acrid by the latex. Latex rather abundant, white, fluid, burning acrid, turning bright yellow-orange with KOH. Spore-deposit white (0–Ia). Pl. 13

 

Chemical reactions. Context immediately dark blue with gaiac, weakly salmon with FeSO4, unchanging with formol, NH4OH and phenol.

 

Basidiospores ellipsoid, 7.7–8.69.4–10.2 × 6.4–7.17.8–8.5 mm (Q = 1.11–1.201.21–1.30, n = 80); ornamentation amyloid, composed of rather regular and rounded warts, connected by fine connective lines, forming an almost complete reticulum; warts up to 0.5 mm high; plage inamyloid. Basidia 55–70 × 10–12 mm, subclavate, 4-spored; content often guttate, sometimes needle-like. Pleurocystidia very abundant, emergent, 65–130 × 8–10 mm, cylindrical to fusiform, rounded, tapering or mucronate at the apex; content needle-like or granular; arising often very deep in the hymenium and thus easily to confuse with pseudocystidia. Pleuropseudocystidia very abundant, 7–10 mm diam., cylindrical to fusiform, mostly with rounded apex; content needle-like or granular. Lamellar edge sterile; cheilopseudocystidia present; marginal cells 16–40 × 5–12 mm, cylindrical to clavate, thin-walled, with guttulate content. Hymenophoral trama irregular, composed of interwoven hyaline hyphae and lactifers. Pileipellis one-layered, composed of interwoven horizontal to ascending hyphae; hyphae thin-walled to very slightly thick-walled, septate, often branched or with short bulges; terminal elements 20–80 × 5–8 mm, cylindrical to tortuous, with rounded apex, with yellowish or reddish brown content (only in the centre of the pileus); laticiferous hyphae abundant in the upper layer; pileocystidia rather abundant, never capitate, cylindrical, with a laticiferous content, 40–80 × 5–7 mm. Stipitipellis idem as pileipellis. Clamp-connections absent. – Fig. 42

 

Ecology. Zambezian miombo woodland. Found under Caesalpiniaceae and Uapaca. In Central Zimbabwe, Lactarius urens is confined to richer miombo woodland with Brachystegia glaucescens on hill ridges. Rather common.

 

Distribution. Known from Burundi, Democratic Republic of Congo, Kenya, Malawi and Zambia, Zimbabwe.

 

Revised specimens

Burundi. Bururi Prov., Rumonge Forest Reserve, Nyamirambo, 9 May 1993, B. Buyck 5089 & 5090 (PC); Ibid., 18 May 1993, B. Buyck 5136 (PC); Ibid., 7 Dec. 1993, B. Buyck 5265 (PC); Ibid., 7 March 1994, A. Verbeken 94-008 (BR 57560–39), 94-014 (BR 57565–44) & 94-016 (BR 57566–45); Ibid., 11 March 1994, A. Verbeken 94-070 (BR 57581–60) & 94-081 (BR 57591–70); Ibid., 15 March 1994, A. Verbeken 94-156 (BR 57610–89); Ibid., 18 March 1994, A. Verbeken 94-212 (BR 57621–03); Ibid., 23 March 1994, A. Verbeken 94-295 (BR 57641–23); Ibid., 25 March 1994, A. Verbeken 94-383 (BR 57652–34) & 94-384 (BR 57653–35); Ibid., 29 March 1994, A. Verbeken 94-443 (BR 57667–49); Ibid., 30 March 1994, A. Verbeken 94-473 (BR 57680–62); Ibid., 31 March 1994, A. Verbeken 94-518 (BR 57688–70); Ibid., 1 April 1994, A. Verbeken 94-558 (BR 57701–83); Mugara, in garden, 16 Nov. 1978, J. Rammeloo 5712 (BR 8767–37); Mugara, 2 Dec. 1978, J. Rammeloo 6002 (BR 18874–56, holotype); Nkayamba, Rumonge, 18 Dec. 1976, F. Dossin 76 (BR 6114–03); Ibid., 14 Dec. 1991, B. Buyck 4026 (PC); Ibid., 12 March 1992, B. Buyck 4245 (PC); Ibid., 20 April 1992, B. Buyck 4377 (PC); Ibid., 29 April 1992, B. Buyck 4424 & 4434 (all PC); Ibid., 15 March 1994, A. Verbeken 94-162 (BR 57615–94); Cankuzo Prov., Murango, 11 March 1994, B. Nzigidahera 59 (PC); Ibid., Dec. 1994, B. Buyck 5625, 5648, 5651 & 5696 (all PC).

Democratic Republic of Congo. Shaba Prov., along road between Lubumbashi and Likasi, 2 Feb. 1986, J. Schreurs 1000 (BR 7849–89); Tshilongo, 3 March 1986, J. Schreurs 1248 (BR 8046–92); Kipopo, 25 km WNW of Lubumbashi, 20 Feb. 1971, D. Thoen 4548 (BR 66224–70); Ibid., 6 March 1971, D. Thoen 4622 (BR 8763–33).

Kenya. Coast Prov., Kwale distr., Arabuko-Sokoke forest reserve, plot 1, 3 Aug 1994, M.H. Ivory 936 (BR 49372–96).

Malawi. Southern Prov., Zomba distr., near R.C. Cathedrale, 5 Jan. 1974, J. Williamson 763 (K(M) 38483); Mulanje distr., nabij Likaubula village, 9 Feb. 2005, F. Noe 05/137 (GENT); Northern Prov., Mzimba distr., Perekezi forest reserve, 28 Jan. 2005, A. Verbeken 05-096 (GENT); Ibid., 18 Feb. 2005, F. Noe 05/353 (GENT); Ibid., 9 March 2005, F. Noe 05/492, 05/460, 05/465 & 05/474-475 (all GENT); Ibid., Ntanga tanga forest reserve, 31 Jan. 2005, F. Noe 05/20 (GENT); Ibid., 15 March 2005, F. Noe 05/551, 05/553 & 05/576-578 (all GENT);

Tanzania. Lake Prov., Mwanza distr., W of Geita, 13 Jan. 1974, D.L. Ebbels F98 (K(M) 38490).

Zambia. Luapala Prov., Mansa, Kwanfumwe, 5 Jan. 1991, B. Buyck 3400 (PC); near Kawambwa, 1431 m alt., 6 Jan. 1991, B. Buyck 3442 (PC); Copperbelt Prov., Mwekera‑forest, between Kitwe & Ndola, 1274 m alt., 21 Jan. 1991, B. Buyck 3481 (PC); Western Prov., Mwinilunga, 1484 m alt., 29 Jan. 1991, B. Buyck 3506 (PC); Northern Prov., Mpika distr., North Luangwa National Park, Mwaleshi Camp, 8 Feb. 1995, D. Shah‑Smith 182 (K(M) 35502); Mbereshi National Forest, 22 Feb. 1998, herb. M. Groenendaal L6.

Zimbabwe. Manicaland Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-201 (GENT); Midlands Prov., Mvuma, Central Estates, Beacon Hill section, at the ostrich incubator, 26 Jan. 1999, A. Verbeken 99-014 (GENT); Ibid., Beacon Hill ridge, 26 Jan. 1999, A. Verbeken 99-014 (GENT); Ibid., 28 Jan. 1999, A. Verbeken 99-038 (GENT).

 

Notes. The description is based on the type and collections of Verbeken from Burundi and Zimbabwe.

     Lactarius urens is easily recognized by its two-coloured cap: reddish brown in the centre with a paler yellowish zone towards the margin, and by its extremely acrid taste. The latex causes a rather heavy burning sensation on unprotected skin, which may last more than one hour.

 

19. Lactarius rufomarginatus Verbeken & Van Rooij

Van Rooij, Nova Hedwigia 77: 235 (2003). − Type: Benin, Borgou Prov., Wari Maro, 21 June 2006, A. De Kesel  3011 (BR 129223–19, holotype; GENT, isotype).

 

Selected descriptions and icons. Van Rooij & al., Nova Hedwigia 77: 235236, 244 (2003).

 

Pileus 61–83 mm diam., slightly infundibuliform to convex and broadly depressed in the centre; margin sometimes striate, undulate and slightly crenulate in older specimens, slightly pruinose in young basidiomes; pellis somewhat wax-like, mat; orange pink to orange brown when young, red to reddish brown when older (8D8–7D8). Lamellae broadly adnate to strongly decurrent, distant (5–8 L+l/cm), broad (6 mm), with a strong venation between the lamellae towards the stipe, forked and veined, pale yellow to yellowish orange (4A3–5A3); lamellulae with an irregular pattern (but usually one lamellula between 2 lamellae); edge reddish brown. Stipe 40–66 × 9–15 mm, long, slender and regularly cylindric; pellis tomentose and mat, orange (6B7–8) to orange brown (6C5–8), becoming orange white towards the base of the stipe, sometimes with a white mycelium. Context (very) thin-fleshed in pileus, solid in the stipe, yellowish white to slightly darker at margin; taste faintly acrid to mild. Latex not observed. Spore-depo­sit not observed. – Pl. 13

 

Basidiospores subglobose to broadly ellipsoid, sometimes globose or ellipsoid, 7.1–7.9–8.2–8.9 × 6.0–6.7–7.3–8.2 µm (Q = 1.02–1.12–1.17–1.33, n = 60); ornamentation amyloid, composed of warts up to 1 µm high, subspherical to subconical, aligned or connected with fine connective lines, forming a distinct reticulum, warts never isolated; plage inamyloid. Basidia 63–75 × 6–10 µm, cylindric to subclavate, sometimes slightly thick-walled, 4-spored (seldom 2-spored), content with oil-like droplets. Pleurocystidia absent. Pleuropseudocystidia abundant, emergent, (3)5–9.5 µm diam., irregularly cylindrical, apex more or less moniliform, sometimes rounded; content needle-like, sometimes granular and with oil-like droplets. Lamellar edge sterile; marginal cells 20–30 × 4–14 µm, subcylindric, thin-walled, hyaline, with a reddish brown pigmentation. Hymenophoral trama cellular with abundant lactifers. Pileipellis ixotrichoderm-like; terminal elements 10–40 × 2–5(7) µm, narrowly cylindric, fusiform to slightly conical, sometimes thick-walled; hyphae sometimes with little knobs, embedded in a thin slime-layer. Stipitipellis idem, terminal elements more frequently slightly thick-walled and not embedded in a slime-layer. Clamp-connections absent. – Fig. 43

 

Ecology. Sudanian riverine forest with Berlinia grandiflora, Lonchocarpus sericeus, Uapaca somon and Pterocarpus erinaceus.

 

Distribution. Only known from the type locality.

 

Revised specimens

Benin. Atacora Prov., Bassila, 21 June 2000, A. De Kesel 2843 (BR 126396–05); Atacora Prov., Bassila, 5 Oct 2000, A. De Kesel 3011 (BR 129223–19, holotype; GENT, isotype) ; Ibid. 11 June 2002, A. De Kesel 3358 (BR 152171–75) ; Ibid. 26 June 2002, A. De Kesel 3470 (BR 152263–70); Ibid., 27 June 2002, A. De Kesel 3481 (BR 152163–67); Ibid. 28 June 2002, A. De Kesel 3487 (BR 152172–76); Ibid., 7 Oct. 2002, A. De Kesel 3524 (BR 152004–05); Ibid. 15 June 2004, A. De Kesel 3613 (BR 157040–94).

 

Notes. The ixotrichoderm structure and the hyphae with little knobs are reminiscent of Lactarius urens Verbeken. The spore ornamentation with rounded warts, connected with fine lines and the irregular cylindrical pleuropseudocystidia are typical for Lactarius section Russulopsidei. Because of its reddish brown cap, the species can be placed next to L. cyanovirescens Verbeken, L. ruvubuensis Verbeken, L. longipes Verbeken and L. urens Verbeken, which all share this character.

 

20. Lactarius pseudotorminosus R. Heim

Heim, Candollea 7: 379 (1938). – Type: Madagascar, S of Soanierana, 8 Dec. 1934, R. Heim G84 (PC, holotype).

 

Selected descriptions and icons. Heim, Prodr. Fl. Mycol. Madagascar 1: 54-56 (1938); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 209210 & Pl. 218220 (1996d).

 

Pileus 50–60 mm diam., rather thick (4–6 mm halfway radius), subtranslucid towards the margin, convex, then uneven and irregular, largely depressed when mature; margin incurved, not involute, straight or deflexed upwards when older; pellis dehiscent, completely and finely tomentose, dry, pale pinkish orange or bright orange. Lamellae decurrent, unequal with abundant lamellulae, rather crowded, narrow (2 mm), thick, cream; edge concolorous, irregularly sinuose. Stipe 30–50 × 10–15 mm, robust, firm, smooth, creamish orange or yellowish white, becoming ochraceous in alcohol and brownish at the base, solid. Context firm, whitish or cream; smell not particular; taste mild. Latex abundant, white; taste mild. Spore-deposit not observed. (According to Heim 1938b).

           

Chemical reactions. Context immediately lilac with FeSO4, intense and positive with gaiac and gaiacol, immediately olive-grey with pyramidon. (According to Heim 1938b).

           

Basidiospores ellipsoid, (6.2–)6.5–7.7–8.8 × (4.7–)5.3–6.2–7.1 mm (Q = 1.15–1.23–1.36, n = 30); ornamentation amyloid, composed of rounded, obtuse warts which are mostly isolated, sometimes aligned or connected by fine connective lines, up to 0.3 mm high; plage inamyloid. Basidia 34–45(–50) × 8–11 mm, cylindrical to subclavate, 4-spored. Pleurocystidia absent. Pleuropseudocystidia abundant, sometimes emergent, (2–)3–5 mm, subcylindrical to tortuous, obtuse or mucronate and tapering upwards, often branched; content oleiferic to granular. Lamellar edge sterile; some very short, deformed basidia present; marginal cells 15–20 × 5–8 mm, fusiform, cylindrical or subclavate, thin-walled; content yellowish, oleiferic. Hymenophoral trama heteromerous, composed of sphaerocytes and some parallel, narrow, hyaline hyphae; lactifers present. Pileipellis a cutis, composed of narrow, hyaline, interwoven hyphae; dermatocystidia abundant, 20–40 × 4–6 mm, cylindrical and mucronate; content granular. Stipitipellis cutis-like, composed of slightly thick-walled hyphae, septate and very frequently branched. Clamp-connections absent. – Fig. 44

 

Ecology. Malagasy lowland rainforest.

 

Distribution. Only known from the type locality.

 

Revised specimens

Madagascar. Betsimisaraka Prov., south of Soanierana, terrestrial, isolated, 8 Dec. 1934, R. Heim G84 (PC, holotype).

 

Notes. The type-specimen consists of one basidiome in quite good condition, but preserved in alcohol.

 

21. Lactarius claricolor  R. Heim

Heim, Candollea 7: 381 (1938). – Type: Madagascar, North of Antanambé, 21 Dec. 1934, R. Heim J18bis (PC, holotype).

 

Selected descriptions and icons. Heim, Prodr. Fl. Mycol. Madagascar 1: 6264 & Pl. 1f (1938); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 210211 & Pl. 221222 (1996d).

 

Pileus 45–60 mm diam., rather thick in the centre, first subumbonate, then strongly depressed and irregular; margin sharp, inflexed, finely and rather long grooved or wrinkled; pellis not dehiscent, tough, almost smooth, finely spotted, dry, pinkish lilac, locally paler, paler at the margin. Lamellae subdecurrent, unequal with numerous lamellulae of different lengths (often short), crowded, narrow (2–2.5 mm), thin, frequently wrinkled in the upper part, ivory white (brownish lilac when preserved in alcohol). Stipe 50–70 × 8–14 mm, long, cylindrical to subfusiform, irregular, wrinkled to grooved, creamish orange to orange-ochraceous, tomentose and whitish at the base with large, membranaceous subiculum, solid. Context white (brownish ochraceous in alcohol), unchanging, tough; smell not particular; taste mild, then acrid. Latex not abundant, white; taste slightly acrid. Spore-deposit white. (According to Heim 1938b). – Pl. 14

 

Chemical reactions. Context immediately pink with FeSO4, positive with gaiac and gaiacol, slightly pale lilac with pyramidon. (According to Heim 1938b).

 

Basidiospores ellipsoid, (6.4–)6.8–7.3–7.8(–8.6) × (5.0–)5.3–5.8–6.3–7.3 mm (Q = 1.17–1.26–1.35, n = 30); ornamentation amyloid, composed of irregularly sized and shaped warts, 0.2–0.5 mm high, which isolated, aligned or connected by fine connective lines, never forming a complete reticulum; plage inamyloid. Basidia 35–45 × 7–9 mm, narrowly clavate, 4-spored. Pleurocystidia absent. Pleuropseudocystidia abundant, (2.5)3–4.5 mm diam., cylindrical to tortuous, with rounded apex, often branched; content densely oleiferic. Lamellar edge sterile; marginal cells 15–35 × 4–6 mm, cylindrical, subcylindrical or tortuous, 2- or 3-septate, with rounded apex, hyaline, thin-walled. Hymenophoral trama subregular, composed of hyaline, narrow hyphae, more or less parallel, lactifers present but rather scarce. Pileipellis composed of interwoven, recumbent to ascending hyphae; terminal cells 13–25 × 2–4 mm, cylindrical, with rounded apex; hyphae sometimes branched and with swollen and isodiametric elements; dermatocystidia rather abundant, 26–36 × 2–4 mm, long, slender, cylindrical, mucronate, capitulate, with some dark brown guttules. Stipitipellis idem. Clamp-connections absent. – Fig. 45

 

Ecology. Found in Malagasy lowland rainforest.

 

Distribution. Only known from the type locality.

 

Revised specimens

Madagascar. Betsimisaraka Prov., North of Antanambé, terrestrial, 21 Dec.1934, R. Heim J18bis (PC, holotype).

 

Notes. The type-specimen consists of one basidiome in rather good condition, preserved in alcohol, which makes it difficult to get a clear picture of the spore-ornamentation.

 

22. Lactarius corbula  R. Heim & Gooss.‑Font.

Heim, Bull. Jard. Bot. Etat Bxl 25: 64 (1955). – Democratic Republic of Congo, Binga, Dec. 1941, M. Goossens-Fontana 2070 (BR 7728–65, holotype).

     Misappl.: Lactarius gymnocarpus ss. Heim (1955) pro parte.

 

Selected descriptions and icons. Bull. Jard. Bot. Etat Bxl 25: 6466, fig. 2ab (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 13, fig. 1b & Pl. 15, fig. 5 (1955); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 213214 & Pl. 230233 (1996d).

 

Pileus 35–90 mm diam., fleshy, convex, then deeply depressed, finely infundibuliform, uneven in the centre; margin deeply grooved up to halfway the radius; pellis partly dehiscent, thin, dry, granulose in the centre, ochraceous brown. Lamellae decurrent, unequal with lamellulae of different lengths (one lamellula between two lamellae), distant (L+l = 2+2/cm), rather broad (up to 9 mm), thick, brittle, anastomosing with fine veins, pale yellow with lemmon shade. Stipe 20–35(–70) × 7–15 mm, shortly cylindrical, tapering downwards, whitish to pale yellowish, solid. Context white, then pale yellowish; taste very acrid, graphite-like; smell not very particular. Latex not abundant in the context, abundant in the lamellae, white, opaque, thick; taste acrid. Spore-deposit white (cream?). (According to Heim 1955a). – Pl. 14

 

Chemical reactions. Context unchanging with alfa-naftol, NH3 and aniline; slowly pinkish with FeSO4; immediately blue-green with gaiac; wine-colour with phenol and immediately chocolate-brown with pyrogallol. (According to Heim 1955a).

 

Basidiospores ellipsoid, 7.0–8.59.0–10.2(–10.4) × 5.3–6.87.3–8.5 mm (Q = 1.13–1.241.26–1.35, n = 60); ornamentation amyloid; composed of conical, pointed to slightly rounded spines, up to 1.5 mm, connected by fine connective lines, forming an almost complete reticulum; plage inamyloid. Basidia 43–60 × 7–12 mm, cylindrical to subclavate, 4-spored; content slightly granular. Pleurocystidia very abundant, often emergent, often arising deep in the subhymenium, 47–70 × 6–10 mm, subcylindrical, with rounded, tapering or slightly mucronate apex; content oleiferic, granular to needle-like. Pleuropseudocystidia rather abundant, often emergent, 6–10 mm diam., subcylindrical, rounded, with tapering or slightly mucronate apex; content oleiferic, needle-like. Lamellar edge sterile; marginal cells 13–37 × 4–6 mm, cylindrical, subclavate or fusiform, sometimes septate; content sometimes granular. Hymenophoral trama composed of narrow, hyaline hyphae and very abundant lactifers. Pileipellis cutis-like; terminal elements 30–50 × 5–7 mm, cylindrical, with rounded apex, sometimes with slightly thickened wall; pileocystida rather abundant, 20–60 × 5–9 mm, with granular or lactiferous content, never capitate. Stipitipellis idem. Clamp-connections absent. – Fig. 46

 

Ecology. Found in drier Guineo‑Congolian rainforest with Gilbertiodendron dewevrei.

 

Distribution. Only known from the type locality.

 

Revised specimens

Democratic Republic of Congo. Equateur Prov., Binga, Apr. 1928, M. Goossens-Fontana 714 (BR 12325–06); Ibid., Sept. 1940, M. Goossens-Fontana 2042 (BR 4921–71); Ibid., Dec. 1941, M. Goossens-Fontana 2070 (BR 7728–65, holotype).

 

Notes. The type consists of numerous basidiomes in mouldy condition.

     Goossens-Fontana 2042 shows the same microscopic characters, however the macroscopic description seems to be based on a Russula-specimen. Especially because of the lack of lamellulae, this can hardly be considered as a Lactarius-description, although, all the macrochemical reactions are the same as those of Goossens-Fontana 2070. Probably, a confusion of specimens has occurred. The microscopic description is based on all revised specimens.

     The species reminds somewhat the species of Lactarius section Chamaeleontini by its deeply grooved pileus and its pileipellis- and stipitipellis-structure, mainly composed of thin-walled hyphae but with some thick-walled terminal elements. However, we do not include Lactarius corbula in L. section Chamaeleontini because of the different aspect of the pileus in the exsiccata (not typical shiny, but rather granulose), the presence of true pleurocystidia, the hymenophoral trama composed of hyphae and not of sphaerocytes and the more cutis-like pilei-and stipitipellis-structure.

     The conspicuous spore-ornamentation, composed of conical, pointed spines, connected by fine connective lines, is only found in Lactarius corbula and L. russuliformis but the pileipellis structure of the latter is completely different.


Sect. Edules  Verbeken

 

Lactarius sect. Edules Verbeken, Belg. J. Bot. 132: 176 “1999” (2000).

Lactarius sect. Russuliformes Verbeken, Mycotaxon 77: 441 (2001).

Type species: Lactarius edulis Verbeken & Buyck.

 

Notes. As molecular data indicate that L. roseolus fits into L. sect. Edules, the section Russuliformes (type species: L. roseolus) becomes a synonym.

 

Key to tropical African species

 

1.  Pileipellis entirely composed of interwoven, long and slender hyphae .........................................  2

     Pileipellis composed of chains of subcylindrical to subspherical elements ..................................  3

 

2.  Taste burning acrid; lamellae distant, pale yellow to golden yellow; pleurocystidia absent ......... 26. L. aureifolius

     Taste mild; lamellae very crowded, cream-colour; pleurocystidia rather abundant ...........  27. L. densifolius

 

3.  Pileus < 3 cm diam., pink to reddish brown, basidiocarp often brittle and delicate ...........  30. L. roseolus

     Pileus larger, basidiocarp mostly firm ......................................  4

 

4.  Lamellae moderately to very distant; stipe short and thick ...........................  5

     Lamellae (very) crowded; stipe long and slender ......................................................  28. L. inversus

 

5.  Pileus somewhat with an olivaceous shade; lamellae dichotomously branched towards the margin; margin of pileus translucently striate ..........................................  29. L. phlebophyllus

     Pileus never with an olivaceous shade; lamellae not dichotomously branched; margin sometimes striate in old specimens, not translucid ...............................................  6

 

6.  Pileus, especially when young, with reddish brown and cinnamon-brown colours; lamellae orange, yellowish orange to pale brownish orange; elements of pileipellis often with small, intracellular, dark granules ...........  25. L. latifolius

     Pileus mainly yellowish to cream-colour, with reddish shade only present in exsiccatum; lamellae cream-colour; elements of pileipellis without intracellular granules ........................................  7

 

7. Spore-ornamentation up to 0.3 µm high, composed of verrucose elements more or less connected; macrocystidia absent .....................  23. L. edulis

     Spore-ornamentation less pronounced, never higher than 0.2 µm; macrocystidia very abundant and as the pseudocystidia with knotty bulges .................................  24. L. nodosicystidiosus

 

Species descriptions

 

23. Lactarius edulis  Verbeken & Buyck

Buyck, Champignons comestibles de l'Ouest du Burundi: 103 (1994). – Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 7 March 1994, A. Verbeken 94-004 (BR 57556–35, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Russulales News 3: 1722 (1995); Härkonen & al., Karstenia 35, Suppl.: fig. 73 (1995); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 159161 & Pl. 110112 (1996d); Karhula & al., Karstenia 38: fig. 20 (1998); De Kesel & al., Guide des champignons comestibles du Bénin: 163 (2002); Härkonen & al., Norrlinia 10: 85 (2003).

 

Pileus 50–150 mm diam., firm and fleshy, planoconvex to applanate and depressed, irregular; margin incurved when young, then straight to irregularly crenulate, yellow to orange when young, paler when old; pellis not dehiscent, dry, slightly felty, cracking towards the margin when older, brownish or greyish orange to yellow, ochraceous, lemmon–colour or cream (5A5, 5B4–5, 6D4–5), with remarkable reddish tinge in exsiccatum. Lamellae slightly decurrent, unequal with lamellulae of different lengths (regular pattern, one or three lamellulae between two lamellae), distant (L+l = 4+3 to 3+7/cm), thick, broad (5–7 mm), cream; edge concolorous, entire. Stipe 30–50 × 20–30 mm, short cylindrical, firm, solid, dry, slightly felty, concolorous to pale orange or yellow (4A3–4, 5A3–4), paler towards the apex. Context very firm, solid, even hard in young basidiomes, white, unchanging, becomes first grey then black when rottening; smell agreeable, sweetish; taste mild. Latex fairly abundant, white; taste mild. Spore-deposit white. – Pl. 14

 

Chemical reactions. Context salmon orange with FeSO4.

 

Basidiospores ellipsoid, 6.8–7.67.8–8.3 × 5.6–6.26.4–7.0 mm (Q = 1.09–1.191.24–1.35, n = 60); ornamentation composed of verrucose, convex to cylindrical elements, < 0.3 mm high, more or less connected, sometimes forming short ridges; plage inamyloid. Basidia 60–80 × 9–11 mm, cylindrical to subclavate, 4-spored. Pleurocystidia absent. Pleuropseudocystidia abundant, 3–5 mm diam., cylindrical, rounded or mucronate. Lamellar edge sterile; marginal cells 15–25 × 5–7 mm, cylindrical, subclavate or slightly fusiform. Hymenophoral trama composed of sphaerocytes; some hyaline hyphae and lactifers present. Pileipellis a trichopalisade, 40–120 mm thick, composed of chains of subcylindrical to subspherical elements, 10–40 × 10–40 mm; terminal elements 10–30 × 5–10, cylindrical to subclavate, sometimes with slightly thickened walls. Stipitipellis a trichopalisade, 40–80 mm thick, composed of chains of subcylindrical to cylindrical elements, 20–30(–40) × 5–10 mm; terminal elements 10–30 × 8–12 mm, cylindrical to subclavate or fusiform. Clamp-connections absent. – Fig. 47

 

Ecology. Miombo woodland, found a.o. under Brachystegia and Uapaca spp.

 

Distribution. Widespread and common in the Zambezian region. Known from Benin, Burundi, Democratic Republic of Congo, Malawi, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Benin. Atacora Prov., Koussou Kouangou, 5 Sept. 1997, A. De Kesel 2063 (BR 74896–12).

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, April 1993, B. Buyck 5067 (PC); March 1994, A. Verbeken 94-004 (BR 57556–35, holotype; GENT, isotype), 94-009 (BR 57561–40), 94-017 (BR 57567–46), 94-079 (BR 57589–68), 94-083 (BR 57594–73), 94-143 (BR 57600–79), 94-144 (BR 57601–80), 94-214 (BR 57622–04), 94-217 (BR 57625–07), 94-275 (BR 57632–14), 94-276 (BR 57633–15)  & 94-447 (BR 57668–50); Ibid., April 1994, A. Verbeken 94-573 (BR 57705–87); Nkayamba, just N of Rumonge, 8 April 1978, J. Lambinon 78/99 (LG); Ibid., April 1992, B. Buyck 4404 (PC); Ibid., Jan. 1993, B. Buyck 4923 (PC); Ibid., Feb. 1993, B. Buyck 4957, 4960 & 4970 (all PC); Ibid., March 1994, A. Verbeken 94-161 (BR 57614–93); Mugara, Feb. 1979, J. Rammeloo 6632 (BR 8778–48); Ruyigi Prov., Ruvubu National Park, April 1994, A. Verbeken 94-646 (BR 57714–96); Cankuzo Prov., forêt claire de Murangu, March 1994, B. Nzigidahera 56 (PC).

Democratic Republic of Congo. Shaba Prov., Biano, Lubudi, 18 March 1990, J. Degreef 90/192 (BR 5115–71); Shilatembo, 12 Dec. 1972, D. Thoen 5579 (BR 7769–09); road between Likasi and Lubumbashi, bought along road side, Jan. 1972, D. Thoen 5287 (Herb. Thoen); Ibid., 3 Dec. 1973, D. Thoen 5742 (BR 66367–19) & 5743 (BR 66368–20).

Malawi. Northern Prov., Mzuzu distr., Katoto, Feb. 1972, J. Williamson 608 (K(M) 38478); Ibid., March 1973, Pawek in J. Williamson 632 (K(M) 38471); Northern Prov., Mzimba distr., Perekezi Forest Reserve, 15 Feb. 2005, F. Noe 05/328 (GENT); Ibid., 11 March 2005, F. Noe 05/502 (GENT); Ibid., 16 March 2005, F. Noe 05/628 (GENT); Southern Prov., Zomba distr., near R.C. Cathedrale, 1 Jan. 1974, J. Williamson 736 (K(M) 38481).

Tanzania. Western Prov., Tabora distr., Tabora, purchased at market, 12 Dec. 1991, T. Saarimäki & al. 1057a (H); Southern Highlands Prov., Iringa distr., Mafinga, Sao Hill Misitu, 6 Feb. 1993, T. Saarimäki & al. 1588 (H).

Zambia. Western Prov., Mwunilinga, 29 Jan. 1991, B. Buyck 3514 (PC); Ibid., 30 Jan 1991, B. Buyck 3536 (PC); Mbereshi National Forest, 22 Feb. 1998, herb. M. Groenendaal L4; road Kawe-Kiposhi, 14 Jan 1996, B. Buyck & G. Eyssartier 96-005 (PC); road Mpongwe-Lusaka (Mikati), 18 Jan. 1996, B. Buyck & G. Eyssartier 96-118 (PC); Miputu, 22 Jan. 1996, B. Buyck & G. Eyssartier 96-005 (PC).

Zimbabwe. Midlands Prov., Mvuma, Mtao Forest Reserve, 28 Jan. 1999, A. Verbeken 99-041 (GENT); Manicaland Prov., Stapleford J. Meikle, 2 Feb. 1999, A. De Kesel 2385 (BR 112555–35).

 

Notes. The species is easily recognized by the firm context, the agreeable sweetish smell and taste and the reddish colour in dried condition. It is a popular edible species throughout the Zambezian miombo region (e.g. Buyck 1994, Härkonen & al. 2003, Parent & Thoen 1977).

 

24. Lactarius nodosicystidiosus  Verbeken & Buyck

Buyck & al., Mycol. Res. 111: 794 (2007) − Type : Madagascar, Arivonimamo, 30 Jan 1997, B. Buyck, G. Eyssartier & P.A. Moreau 97-092 (PC, holotype; GENT, isotype).

 

Pileus 50–100 mm diam., convex to planoconvex, first with incurved margin, later with rather irregular, wavy margin; surface smooth, dry, slightly velvety and pruinose, cream to pale yellowish orange. Stipe 20–40 × 10–15 mm, cylindric, robust, solid; surface similar to pileipellis. Lamellae broadly adnate, distant, with lamellulae of different lenghts, cream; edge entire, concolorous. Context firm, pale.

 

Spores subglobose to broadly ellipsoid, rarely ellipsoid, 7.5–8.5–8.6–9.8 × 6.2–7.3–7.6–8.7 µm (Q = 1.03–1.13–1.18–1.39, n = 40; ornamentation amyloid, but very low and weakly developed, composed of indistinct, very low warts, sometimes aligned or connected by narrow lines, not exceeding 0.2 µm; plage inamyloid. Basidia 50–70 × 8–12 µm, 4-spored, rarely 2-spored, long, narrow, subcylindrical; sterigmata often long and sometimes swollen in the middle. Pleuromacrocystidia and pleuropseudocystidia very abundant and very similar. Pleuromacrocystidia slightly emergent, often originating deep in the hymenium, 75–110 × 5–9 µm, thin-walled, subcylindric, somewhat tapering near apex, often with very irregular apex, with bulges or moniliform; content opaque oil-like or needle-like. Pleuropseudocystidia slightly emergent, similar in shape to the pleuromacrocystidia, with irregular apex, often moniliform or with bulges and branching, up to 7(12) µm broad; content oil-like or needle like. Lamellar edge sterile; marginal cells subcylindric to somewhat irregular or slightly subclavate, 20–45 × 6–9 µm, thin-walled, hyaline. Pileipellis a trichopalisade, composed of chains of small (usually less than 15 µm diam.), rounded cells, with long, narrow cylindric elements on top; terminal elements 30–60 × 3–5 µm, regularly cylindric, usually oblique to pericline, forming a rather densily interwoven layer of 30–60 µm thick on top of the sphaerocytes. Stipitipellis similar. Clamp-connections absent. – Fig. 48

 

Ecology. Found in Uapaca bojeri woodland.

 

Distribution. Only known from Madagascar.

 

Revised specimens

Madagascar. Arivonimamo, 30 Jan. 1997, B. Buyck & al. 97-072 (PC, holotype; GENT, isotype), B. Buyck & al. 97-045b (PC); Ibid., 5 Feb. 1997, B. Buyck & al. 97-273 (PC); Fiadanana village along RN7, 32 km from Antsirabe direction Ambositra, 10 Feb. 2000, B. Buyck 00-1336 (PC).

 

Notes. The microscopical description is based on Buyck 97-273 & 97-072.

     Lactarius nodosicystidiosus is very similar to L. edulis. Both species share the pale overall colour, the robust, firm habit and the distant, broad lamellae. Under the microscope, however, the pileipellis structure of L. edulis shows a thicker, more loosely arranged pileipellis having the cylindrical terminal elements more dispersed and not forming a distinct superficial layer. Also the spore-ornamentation is more pronounced in L. edulis and spores are slightly smaller (on average 7.7 × 6.3 µm). Pseudocystidia as well as macrocystidia are strikingly abundant in L. nodosicystidiosus, while only pseudocystidia are present in L. edulis.

 

25. Lactarius latifolius  Gooss.‑Font. & R. Heim

Heim, Bull. Jard. Bot. Etat Bxl 25: 82 (1955). – Type: Democratic Republic of Congo, Binga, Feb. 1935, M. Goossens-Fontana 1009 (BR 7726–63, holotype).

     Lactarius cinnamomeus  Gooss.‑Font. & R. Heim in Heim, Bull. Jard. Bot. Etat Bxl 25: 32 (1955), illegit., non Lactarius cinnamomeus W.F. Chiu (1945).

 

Selected descriptions and icons. Heim, Bull. Jard. Bot. Etat Bxl 25: 3235, 8285 & Pl. 2, fig. 2ad & Pl. 4, fig 3ac (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 14, fig. 1 & Pl. 15, fig. 1 (1955); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 113116 & Pl. 161162 (1996d); Verbeken & Walleyn, Belg. J. Bot. 132: 177, 179181 (2000).

 

Pileus 40–150 mm diam., firm, fleshy, convex to applanate, soon depressed, finally subinfundibu­liform; margin first involute and curved, then very irregular and undulate, sometimes with cerebriform, sinuose and concentrical veins, striate to grooved when older; pellis not dehiscent, felty, finely cracking, orange-brown to reddish brown when young, cinnamon-brown, then rather polychrome, yellowish ochraceous, lemon-yellow in the centre, with violet-cinnamon shade in exsiccatum. Lamellae adnate to decurrent with teeth, unequal with a few lamellulae of different lengths, very distant (40/total), very thick, moderately broad, brittle, anastomosing with thick veins, orange, yellowish orange to pale brownish orange, with lilac shade in exsiccatum. Stipe 40 × 20–25 mm, short, thick, cylindrical, slightly tapering downwards, finely felty, brownish pale pink, cinnamon-colour or orange-brown, paler at the base, cream and faded lilac in exsiccatum, firm, solid. Context brittle, white, sometimes becoming yellowish; taste variable; smell not particular. Latex abundant, white; taste variable. Spore-deposit whitish, cream. (According to Heim 1955a). – Pl. 14

 

Chemical reactions. Context immediately blue (Goossens-Fontana 3062) or nihil (Goossens-Fontana 2074 & 3025) with aniline; immediately pale pink with FeSO4 (Goossens-Fontana 2074, 3025 & 3062); slowly blue-green (Goossens-Fontana 2074, 3025 & 3062) or immediately blue-green (Goossens-Fontana 1009) with gaiac; unchanging with naphthol (Goossens-Fontana 2074) and NH4OH (Goossens-Fontana 2074, 3025 & 3062); wine-colour to blackish with phenol (Goossens-Fontana 2074 & 3062); immediately brown (Goossens-Fontana 2074 & 3062) or slowly yellowish brown (Goossens-Fontana 1009 & 3025) with pyrogallol. Lamellae immediately brown with FeSO4 (Goossens-Fontana 1009). (According to Heim 1955a).

 

Basidiospores subglobose to ellipsoid, 6.2–6.57.9–8.8(–9.2) × 5.0–5.7–6.9–7.6(–8.0) µm (Q = 1.03–1.14–1.19–1.28, n = 80); ornamentation amyloid, low, composed of rounded to irregularly shaped warts, connected by fine connective lines, forming an almost complete reticulum, < 0.3 µm high; plage inamyloid. Basidia (35–)50–67 × (5–)8–12 µm, cylindrical to subcylindrical, long and slender, 4-spored; content granular. Pleurocystidia absent. Pleuropseudocystidia abundant, slightly emergent, 7–12 µm diam., cylindrical or fusiform, with tapering or rounded apex; content oleiferic. Lamellar edge sterile; marginal cells 16–45 × 4–5 µm, cylindrical to tortuous, with rounded or tapering, sometimes mucronate apex, thin-walled, hyaline. Hymenophoral trama composed of sphaerocytes; some hyaline hyphae and lactifers present. Pileipellis a trichopalisade, composed of chains of isodiametric to irregular cells, often with incrusting pigments; isodiametric cells 20–30 µm diam.; terminal elements (20–)30–50 × 5–6 µm, cylindrical, slender, with rounded apex, sometimes fusiform and up to 12 µm diam., often with small, intracellular, dark granules (not indicated in figure). Stipitipellis cutis-like, composed of hyaline hyphae; hyphae branched, septate, more or less parallel; lactifers present; hyphae at the base of the stipe with slightly thickened walls. Clamp-connections absent. – Fig. 49

 

Ecology. Drier Guineo‑Congolian rainforest.

 

Distribution. Known from the Democratic Republic of Congo and Gabon.

 

Revised specimens

Democratic Republic of Congo. Equateur Prov., Binga, ca. 1928, M. Goossens-Fontana 866 (BR 4968–21); Ibid., Feb. 1935, M. Goossens-Fontana 1009 (BR 7726–63, holotype, consisting of 5 basidiomes in very poor condition); Ibid., Nov. 1945, M. Goossens-Fontana 2074 (BR 5007–60); Ibid., Jan. 1943, M. Goossens-Fontana 3025 (BR 7730–67); Ibid., Nov. 1946, M. Goossens-Fontana 3062 (BR 7731–68).

Gabon. Research Station of Ipassa-Makokou, 24 March 2005, S. Dibaluka Mpulusu 37 (BR 164536–24).

 

Notes. Heim (1955b) already mentioned that Lactarius cinnamomeus Gooss.-Font. & R. Heim has identical microscopic characters as L. latifolius, but indicated the absence of gelified veins in L. latifolius and differences in taste of the context (acrid in L. cinnamomeus) as discriminating characters. As for the taste, we consider this character as very doubtful, as in fact the fieldnotes accompanying Goossens-Fontana 3062 mention a mild taste. As to the gelified veins on the pileus, they are probably only present in young basidiomes and the exsiccata of the syntypes of Lactarius cinnamomeus show smooth and very regular pileal surfaces, just like those of L. latifolius.

 

26. Lactarius aureifolius  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 198 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 11 March 1994, A. Verbeken 94-005 (BR 57557–36, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 164165 & Pl. 125128 (1996d); Verbeken & Walleyn, Belg. J. Bot. 132: 177179 (2000); Verbeken, Micol. Veget. Medit. 16: fig. 2 (2001).

 

Pileus 30–120 mm diam., thick, fleshy, firm, convex when young, then planoconvex to applanate, finally depressed to infundibuliform; margin involute when young, then straight or slightly deflexed upwards, regular or crenulate; pellis dehiscent up to halfway the pileus, dry, mat, finely felty, cracking when older, pale yellow (4A3–4) when young, pale orange to greyish orange (5A3 to 5B4), brownish in the centre when older, sometimes with pinkish shade. Lamellae adnate to slightly decurrent, unequal with lamellulae of two different lengths (regular pattern, 3(–5) lamellulae between two lamellae), distant (L+l = 2+5 to 3+8/cm, exceptionally 5+15/cm), broad (3–10 mm), rather thick, firm then brittle, sometimes anastomosing and dichotomously branched, pale yellow to deep yellow, orange yellow (4A5–8); edge entire, brighter than lamella when young, more orange when old. Stipe (15–)25–55 × 15–35 mm, short cylindrical, sometimes tapering downwards, dry, mat, finely cracking, pale yellow to pale orange, somewhat paler than pileus, whitish downy at the base, solid. Context firm, 8–10 mm in pileus, white to cream, changing locally pale orange when cut; smell agreeable, sweetish, rhubarb-like, apple-like; taste very acrid, burning. Latex abundant to very abundant, fluid, white, unchanging; taste very acrid, burning. Spore-deposit white. – Pl. 15

 

Chemical reactions. Context salmon pink to orange to greyish with FeSO4; unchanging with HCl; unchanging or yellow with KOH. Pileipellis olive brown with KOH, unchanging or somewhat yellow with NH4OH.

 

Basidiospores ellipsoid, 6.7–7.6–7.8–8.8 × 5.7–6.2–6.5–7.2 µm (Q = 1.12–1.21–1.22–1.33, n = 60); ornamentation amyloid, composed of low, irregularly sized and shaped warts, often aligned or connected by fine lines, never forming a complete reticulum, < 0.2 µm; plage with central amyloid spot. Basidia 50–80 × 6–8 µm, cylindrical to subclavate, long and slender, 4-spored; content sometimes guttate. Pleurocystidia absent. Pleuropseudocystidia rather abundant, 4–9 µm diam., cylindrical to clavate, with rounded apex. Lamellar edge sterile; marginal cells 15–25 × 3–6 µm, cylindrical to subfusiform, hyaline, thin-walled. Hymenophoral trama composed of small sphaerocytes and abundant lactifers, a few hyaline hyphae present. Pileipellis a trichoderm, composed of interwoven hyphae; hyphae 4–6 µm diam., long, slender, often septate, sometimes branched, very slightly thick-walled; terminal elements not aberrant, 15–30 × 4–6 µm, cylindrical, rounded at the apex. Stipitipellis idem; some intracellular granules observed. Clamp-connections absent. – Fig. 50

 

Ecology. Zambezian miombo woodland with dominance of Brachystegia spp.

 

Distribution. Known from Burundi, Democratic Republic of Congo, Malawi, Zambia and Zimbabwe. Not common.

 

Revised specimens

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, March 1994, A. Verbeken 94-005 (BR 57557–36, holotype; GENT, isotype), 94-032 (BR 57572–51), 94-076 (BR 57586–65), 94-273 (BR 57630–12), 94-350 (BR 57649–31)  & 94-536 (BR 57695–77); Ibid., April 1994, A. Verbeken 94-556 (BR 57698–80).

Democratic Republic of Congo. Shaba Prov., Kipopo, 9 Jan. 1961, M.C. Schmitz-Levecq 293 (BR 12294–72).

Malawi. Southern Prov., Machinga distr., Liwonde Forest Reserve, 4 Feb. 2005, A. Verbeken 05-207 & 05-209 (all GENT).

Zambia. Farm Gibsons, 23 Jan. 1996, B. Buyck & G. Eyssartier 96-157 (PC).

Zimbabwe. Manicaland Prov., Penhalonga, hill behind Harris’, 9 Feb. 1999, A. Verbeken 99-153 (GENT); Manicaland Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-199 (GENT).

 

Notes. This species is easily recognized in the field by its deep yellow to golden yellow lamellae and the very acrid to burning taste of the latex. These outstanding differences not taken in account, it could be confused with Lactarius edulis, from which it is microscopically also very different by the lack of isodiametric or inflated elements in the pileipellis.

 

27. Lactarius densifolius Verbeken & Karhula

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 200 (1996). – Type: Zambia, Mwunilunga, 30 Jan. 1991, B. Buyck 3601 (BR 38487–75, holotype; PC, isotype).

     Misappl.: Lactarius inversus ss. Buyck (1994) & Buyck & Nzigidahera (1996); L. piperatus ss. Pegler & Piearce (1980).

     Excl.: L. densifolius ss. Van Rooij & al. (2003), De Kesel & al. (2002), = Lactarius sp.

 

Selected descriptions and icons. Buyck, Champignons comestibles de l'Ouest du Burundi: 105, fig. 79 (1994: as "inversus"); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 165167 & Pl. 129133 (1996d) ; Verbeken & Walleyn, Belg. J. Bot. 132: 177, 179180 (2000); Karhula & al., Karstenia 38: fig. 21 (1998); Härkonen & al., Norrlinia 10: 84 (2003).

 

Pileus 30–70 mm diam., firm, fleshy, planoconvex to applanate, then deeply depressed to infundibuliform; margin involute, sometimes becoming reflexed when older; pellis not dehiscent, dry, finely tomentose, typically rupturing into small, felty fields, pale brownish yellow or apricot orange to cream. Lamellae decurrent, unequal with lamellulae of different lengths, very dense, very narrow, cream; edge entire, concolorous. Stipe 40–60 × 12–25 mm, cylindrical, concolorous with the pileus, firm, solid. Context firm, white, unchanging; taste mild. Latex white to transparent, unchanging; taste mild. Spore-deposit white.

 

Basidiospores subglobose to ellipsoid, (7.5–)8.0–8.7–9.4(–9.7) × (6.5–)6.8–7.6–8.5(–8.7) µm (Q = 1.04–1.14–1.25, n = 40); ornamentation amyloid, composed of small and irregularly shaped warts, aligned or connected by fine lines, not exceeding 0.2 µm height; plage inamyloid. Basidia 55–70 × 9–11 µm, subcylindrical to subclavate, long and slender, 4-spored, sometimes 2-spored; content guttate. Pleurocystidia rather abundant, arising deep in the subhymenium, sometimes slightly emergent, (80–)90–110(–120) × 4–6 µm, long and slender, cylindrical, almost moniliform at the apex, sometimes branched; content hyaline or oleiferic. Pleuropseudocystidia rather abundant, slightly emergent, 4–6 µm, slender, cylindrical or slightly tortuous, almost moniliform at the apex, sometimes branched; content oleiferic. Lamellar edge sterile; marginal cells 15–50 × 4–7 µm, cylindrical to subclavate, with rounded apex, thin-walled, hyaline. Hymenophoral trama composed of sphaerocytes; sphaerocytes especially abundant in the central part, also mixed with thin-walled, hyaline hyphae which are more abundant near the subhymenium; lactifers present. Pileipellis a trichoderm; elements of the suprapellis 20–80 × 3–5 µm, long and slender, cylindrical, frequently septate, with rounded apex, sometimes with incrustrated wall, sometimes with small bulges, thin-walled, hyaline, but sometimes guttate; subpellis composed of hyphae, with some isodiametric or irregularly shaped cells. Stipitipellis trichoderm-like; elements of the suprapellis 20–50 × 3–5 µm, cylindrical, slender, with rounded apex, frequently septate, sometimes branched, with slightly thickened wall, becoming much more longer and more thick-walled near the base of the stipe; subpellis composed of parallel hyphae and lactifers, no isodiametric cells. Clamp-connections absent. – Fig. 51

 

Ecology. Zambezian miombo woodland.

 

Distribution. Widespread in the Zambezian region. Known from Burundi, Democratic Republic of Congo, Malawi, Tanzania and Zambia.

 

Revised specimens

Burundi. Cankuzo Prov., forêt claire de Murangu, Dec. 1994, B. Buyck s.n. (PC).

Democratic Republic of Congo. Shaba Prov., Kipopo, 14 March 1959, M.C. Schmitz‑Levecq 105 (BR 6123–12).

Malawi. Southern Prov., Makwawa, Zomba, 29 Jan. 1980, B. Morris 82 (K(M) 38468); Southern Prov., Machinga distr., near Machinga, Malosa Forest Reserve, 25 Jan. 2005, A. Verbeken 05-062 (GENT); Northern Prov., Mzimba distr., Perekezi Forest Reserve, 9 March 2005, F. Noe 05/455 (GENT); Ibid., 11 March 2005, F. Noe 05/504, 05/510 & 05/514 (all GENT).

Tanzania. Southern Prov., Songea distr., Matomondo, 29 km from Songea towards Mbinga, 29 Jan. 1993, T. Saarimäki & al. 1449 (H); Ibid., Lirondo, 30 Jan. 1993, T. Saarimäki & al. 1468 (H); Southern Highlands Prov., Kidugala, 30 Jan. 1993, T. Saarimäki & al. 1474 (H); Ibid., Njombe distr., Ngaramiro, 2 km N of Kidugala, 31 Jan. 1993, T. Saarimäki & al. 1479 & 1489 (all H); Ibid., between Sengele and Masaulwa, N of Kidugala, 2 Feb. 1993, T. Saarimäki & al. 1524 & 1543 (all H).

Zambia. Western Prov., Mwunilunga, 30 Jan. 1991, B. Buyck 3601 (BR 38487–75, holotype; PC, isotype); Luapala Prov., Mansa, Kwanfumwe, 2 Jan. 1991, B. Buyck 3311 (PC); Copperbelt Prov., Kitwe, 21 Dec. 1977, G. Piearce FP600/1a (K(M) 34213); Miputu, 22 Jan. 1996, B. Buyck & G. Eyssartier 96-150 (PC).

 

Notes. This species is edible, and well appreciated in the Zambezian miombo area (e.g. Buyck 1994, Härkonen & al. 2003, Pegler & Piearce 1980).

     The species was recorded for Benin (Van Rooij & al. 2003, De Kesel & al. 2002) but the concerning specimen (Borgou Prov., Wari Maro, 24 Sept 1998, De Kesel 2324) represents another species. The spore ornamentation consists of larger and more regular warts with less connections.

 

28. Lactarius inversus  Gooss.‑Font. & R. Heim

Heim, Bull. Jard. Bot. Etat Bxl 25: 78 (1955). – Type: Democratic Republic of Congo, Binga, Nov. 1945, M. Goossens-Fontana 3063 (BR 7732–69, holotype).

     Excl.: Lactarius inversus ss. Buyck (1994, = Lactarius densifolius).

 

Selected descriptions and icons. Heim, Bull. Jard. Bot. Etat Bxl 25: 7882 & Pl. 3, fig. 2 (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 15, fig. 2 (1955); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 163164 & Pl. 120124 (1996d).

 

Pileus 30–100 mm diam., convex, becoming more and more depressed, finally infundibuliform; margin incurved, then straight and irregular; pellis not dehiscent, slightly velvety, tomentose, cracking into small, felty, darker flocks, sienna-colour, brownish to yellowish orange, becoming more orange when older, more reddish in exsiccatum; veins towards the margin slender, concolorous, concentrical and sinuose, later varicose and radial. Lamellae decurrent with long teeth, unequal with lamellulae of two different lengths, veined to anastomosing, crowded, narrow (< 4 mm), pale yellow to yellowish cream; edge entire, concolorous. Stipe (30–)40–65 × 10–15 mm, firm, long cylindrical, rounded at the base, felty, with longitudinal veins in the upper third, brownish orange as pileus, more yellowish orange when young, cinnamon with some red areas when old. Context firm, brittle, white, becoming slightly yellowish; taste mild; smell acrid. Latex abundant, white, transparent, unchanging; taste mild, sweet. Spore-deposit not observed. – Pl. 16

 

Chemical reactions. Context unchanging with aniline; slowly blue-green with gaiac; slowly pinkish with Fe SO4; brown with pyrogallol; immediately wine-colour with phenol; unchanging with NH3. (according to Heim 1955a)

 

Basidiospores subglobose to ellipsoid, 6.3–7.3–8.0–8.9 × 5.3–6.1–6.9–7.6 mm (Q = 1.06–1.17–1.20–1.35, n = 50); ornamentation amyloid, composed of globose to irregular warts, often isolated, sometimes connected by fine connective lines, < 0.2 mm; plage sometimes with central amyloid spot. Basidia 40–55 × 7–10 mm, cylindrical to subclavate, 4-spored, often 2-spored and then sterigmata up to 17 mm. Pleurocystidia scarce, 50–65 × 6–8 mm, cylindrical to subclavate with remarkable mucronate to rostrate apex, hyaline, thin-walled, giving the impression to be deformed, monosterigmatic basidia. Pleuropseudocystidia moderately abundant, 4–8 mm diam., cylindrical to tortuose, hardly emergent; content oleiferic. Lamellar edge mixed; basidia present, 30–40 × 7–9 mm; marginal cells 10–40 × 5–10 mm, cylindrical to clavate, hyaline, thin-walled. Hymenophoral trama composed of sphaerocytes and lactifers. Pileipellis a trichopalisade, composed of isodiametric to pyriform or irregular cells which are 30–40 mm diam., with slightly thickened and often incrustated walls, mostly forming chains; terminal cells 15–35 × 5–10 mm, cylindrical to pyriform, with slightly thickened and often incrustated walls. Stipitipellis idem as pileipellis. Clamp-connections absent. – Fig. 52

 

Ecology. Drier Guineo‑Congolian rainforest, lowland humid rainforest.

 

Distribution. Known from Cameroon, Democratic Republic of Congo and Guinea.

 

Revised specimens

Cameroon. South Western Prov., near Mundema, Korup National Park, transect P10, 27 March 1991, R. Watling 24174 (E).

Democratic Republic of Congo. Equateur Prov., Binga, terrestrial, Nov. 1945, M. Goossens-Fontana 3063 (BR 7732–69, holotype).

Guinea. Forêt humide de Ziama, arboretum des stagiaires, 1 Aug. 1999, A. Bâ 168 (GENT).

 

Notes. The type consists of 4 basidiomes in rather good condition.

     The macroscopic description is based on the description of Heim (1955a), completed with fieldnotes of Watling. The microscopic description is based on both specimens.

     The species is recognized in the section by the dense lamellae, a character shared with Lactarius densifolius, but differs from the latter by the reddish colours of the pileus and the pileipellis which is here a trichopalisade whereas a trichoderm in L. densifolius.

 

29. Lactarius phlebophyllus R. Heim

Heim, Candollea 7: 378 (1938). – Type: Madagascar, Anosibé, S of Soanierana, 8 Dec. 1934, R. Heim G87 (PC, holotype).

 

Selected descriptions and icons. Heim, Prodr. Fl. Mycol. Madagascar 1: 5253 (1938); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 162163 & Pl. 117119 (1996d); Buyck & al., Mycol. Res. 111: 792794 (2007).

 

Pileus 30–100 mm diam., thin, convex to planoconcave and slightly depressed in the centre, then depressed, irregular; margin translucid, striate by the lamellae; pellis tomentose, spotted, cracking into small areolate fields in mature specimens, smooth in the centre, dry, ochraceous orange, brownish orange, subolivaceous, very pruinose and pale especially in young specimens, in older specimens more brownish orange in the centre; margin somewhat brighter and golden yellow in young specimens, becoming ochraceous and irregularly undulate in older specimens. Lamellae broadly adnate to decurrent with small tooth, rather crowded to distant, brittle, narrow (up to 3 mm), thin, anastomosing with abundant lateral veins, dichotomously branched near the margin or often forked at different distances, cream, creamish orange; edge entire, concolorous or slightly paler. Stipe 35–50 × 10–20 mm, robust, tapering downwards, sometimes irregular and compressed, finely tomentose, orange, slightly ochraceous, pale ochraceous and somewhat more yellowish than the pileus, whitish at the apex, solid. Context firm, cream, unchanging; smell not particular; taste mild. Latex white, rather abundant in young specimens, unchanging; taste mild. Spore-deposit white. – Pl. 16 & 17

 

Basidiospores subglobose to ellipsoid, seldom globose, 6.4–7.77.9–9.0 × 5.5–6.47.0–7.6 mm (Q = 1.01–1.131.22–1.40, n = 50); ornamentation amyloid, very low, up to 0.3(–0.5) µm high, composed of irregular warts which are isolated or sometimes aligned or connected by fine lines, forming an incomplete reticulum; plage inamyloid. Basidia 40–60 × 7–12 mm, cylindrical to subclavate, 4-spored, with rather broad sterigmata which are 5–8 µm long, slightly thick-walled at the base. Pleurocystidia absent. Pleuropseudocystidia not very abundant, not or hardly emergent, subcylindrical to irregularly tortuose and with often very tortuous, branching apex, sometimes with some bulges, 5–10(12) µm diam.; content densely oleiferic, slightly guttate. Lamellar edge sterile; marginal cells 10–75 × 4–8 mm, narrowly cylindrical, subclavate, thin-walled, hyaline. Hymenophoral trama composed of rather small sphaerocytes; lactifers scarce. Pileipellis a trichopalisade, up to 150 µm thick, composed of isodiametric to elongate cells, 10–45 × 7–20 mm, mostly forming chains; terminal elements 15–60 × 5–15 mm, cylindrical or fusiform, tapering upwards. Stipitipellis similar to pileipellis structure. Clamp-connections absent. – Fig. 53

 

Distribution. Only known from Madagascar.

 

Ecology. Described from Malagasy lowland rainforest, and found recently in dry dense forest with dominance of Uapaca densifolia, Sarcolaena multiflora and Leptolaena pauciflora.

Revised specimens

Madagascar. Betsimisaraka Prov., Anosibé, S of Soanierana, terrestrial, Dec. 1934, R. Heim G87 (PC, holotype); Ambohitantely Natural Reserve, N of Ankazobe, 15 Feb. 2000, B. Buyck 00-1388 & 00-1400 (all PC).

 

Notes. The type of L. phlebophyllus, consists of half a basidiome in bad condition. This description is based on the type material and on the recently collected specimens from Madagascar (Buyck & al. 2007).

     Lactarius phlebophyllus is a striking species because of the overall uniform, yellowish colour, the areolate pileus and the very narrow, almost regularly forked gills. Heim (1938b) described the gills as ‘distant’, but our own observations on the type contradicted this and showed both collections to be exactly comparable in this respect.

     Spore characters and pileipellis structure are strictly comparable, but there are some minor microscopical differences between our observations made on the type specimen and those on the recently collected material. Pleuropseudocystidia are present in both, but more scarce in the type material. The narrow and very long marginal cells of the gill edge in the recent collection have not been observed on the type.

 

30. Lactarius roseolus Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 207 (1996). – Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 23 March 1994, A. Verbeken 94-274 (BR 57631–13, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 222223 & Pl. 252254 (1996d); Verbeken & al., Syst. Geogr. Pl. 70: 203205 (2000); Verbeken, Micol. Veget. Medit. 16: fig. 4 (2001).

 

Pileus (5–)10–31 mm diam., very thin, very delicate and brittle, planoconvex to applanate and slightly infundibuliform, weakly depressed, sometimes with a very small central umbo inside that depression; margin regular, finely but distinctly crenulate, faintly striate, grooved in older specimens; pellis not dehiscent, soft, dry, chamois-leather-like to felty, sometimes slightly rugulose in older specimens, pale orange to pastel red (6A3 to 7A4 to 8A5), dark reddish brown (7E–F8), brownish orange (6D6), paler orange when older, paler and almost white towards the margin. Lamel­lae adnate to slightly or strongly decurrent, unequal with lamellulae of different lengths (0–3 lamellulae between 2 lamellae), distant (total number L = 32–40), narrow (1–2 mm), fairly thick, white to cream (3A2 to 4A2), with some furcations; edge entire, concolorous. Stipe 10–30 × 1–6 mm, a bit irregularly cylindric, slender, often tapering downwards; pellis smooth or more often finely cracked or a bit sqamulose which makes it looks spotted on a whitish background, concolorous with pileus or a bit paler, pastel red to greyish red (7A4–5), whitish at the base, very contrasting with the white lamellae and sometimes with a distinct separation in colour just underneath the sometimes decurrent teeth. Context thin in pileus, fistulose or multi-chambered in stipe, fragile, white, unchanging; taste fresh, mild, slightly menthol-like; smell not particular. Latex quite abundant, white or watery, unchanging; taste mild. Spore-depo­sit white. – Pl. 18

 

Chemical reactions. Context salmon with FeSO4, unchanging with gaiac.

 

Basidiospores subglobose to ellipsoid, 7.0–7.87.9–8.6 × 6.0–6.97.0–7.6(–7.9) mm (Q = 1.05–1.111.13–1.25; n = 60); ornamentation not very distinct, very low and irregular, composed of irregularly shaped and sized warts and connective lines; plage inamyloid. Basidia 50–70 × 7–10 mm, cylindrical to subcylindrical, long and slender, 4-spored. Pleurocystidia absent. Pleuropseudocystidia scarce, 3–5 mm diam., cylindrical to tortuous, sometimes branched; content oleiferic. Lamellar edge fertile, no marginal cells observed. Hymenophoral trama heteromerous, composed of sphaerocytes; lactifers fairly abundant. Pileipellis a palisade, hymeniderm-like; elements of suprapellis 20–60 × 5–10 mm, cylindrical to fusiform, sometimes septate, hyaline, thin-walled; subpellis pseudoparenchymatous, composed of isodiametric cells. Stipitipel­lis a trichoderm; terminal elements 10–50 × 4–10 mm, cylindrical to fusiform, sometimes septate, hyaline, thin-walled, connected with slender hyphae which are forming an underlaying layer. Clamp-connections absent. – Fig. 54

 

Ecology. Miombo woodland with Brachystegia spp.

 

Distribution. Only known from Burundi and Zimbabwe.

 

Revised specimens

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, 11 March 1994, A. Verbeken 94-064 (BR 57575–54); Ibid., 23 March 1994, A. Verbeken 94-274 (BR 57631–13, holotype; GENT, isotype); Ibid., 25 March 1994, A. Verbeken 94-343 (BR 57644–26); Road Kigwena to Vianda, 6 May 1982, C. Cocquyt 336 (GENT).

Zimbabwe. Manicaland Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-207 & 99-208 (all GENT); Manicaland Prov., Burma valley road, 20 km from turnoff “cloudland”, 10 Feb. 1999, A. Verbeken 99-159 & 99-160 (all GENT); Manicaland Prov., above Bridal Veil Road, Chimanimani, 26 Jan. 1999, D. Arora 99-50 (SFSU); Manicaland Prov., Eastern Highlands, Mguzu, 5 Feb. 1999, Gansemans in A. De Kesel 2740 (BR 115760–39); Ibid., 6 Feb. 1999, A. De Kesel 2421 (BR 112591–71).

 

Notes. The collection Verbeken 99-159 from Zimbabwe consisted of stouter, darker coloured and more reddish brown (the colour of the red banded ironstone) specimens than the small pale pinkish specimens from Burundi, that were mostly collected as single specimens. Because the Burundi and Zimbabwe specimens are microscopically fully identical, we do not believe that these differences have taxonomic value.

     Specimens of one collection, Arora 99-50, had a very strong smell of grated coconut (macaroons), which was absent in the other collections. Conspicuous differences in smell were also observed in other African Lactarius species such as L. saponaceus.


Sect. Aurantiifolii Verbeken

 

Lactarius sect. Aurantiifolii Verbeken, Mycotaxon 77: 441 (2001).

Type species: Lactarius aurantiifolius Verbeken.

 

Species description

  

31. Lactarius aurantiifolius Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 197 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 11 March 1994, A. Verbeken 94-063 (BR 57574–53, holotype; GENT, isotype).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 167168 & Pl. 134138 (1996d); Verbeken & al., Syst. Geogr. Pl. 70: 185187 (2000); Verbeken, Micol. Veget. Medit. 16: fig. 1 (2001).

 

Pileus 17–50 mm diam., thin, convex to planoconvex and applanate, finely infundibuliform, slightly depressed; margin incurved when young, then straight and regular; pellis not dehiscent, dry, very pruinose when young, felty (with distinct erect hairs in young specimens, lens!) to smooth when older, concentrically zoned (more distinct in center, often vague towards margin), orange white to pale orange (5A2–7), orange in the centre (6AB6), whitish pruinose (5A2–3) when young. Lamel­lae adnate to slightly decurrent, unequal with 1–3 lamellulae between 2 lamellae (regular pattern), crowded to moderately distant (L+l = 3+7 to 5+13/cm), with abundant lamellulae from different lenghts, thin, narrow (2–3 mm), paper-like, veined when older, sometimes anastomosing, deep orange (5A6–7); edge paler, whitish, appendiculate to fimbriate, with watery tears. Stipe 10–70 × 4–16 mm, cylindrical, strongly tapering downwards, knotty, dry, felty, orange white to pale orange (4A4 to 5A2–4), whitish pruinose (remaining so in the exsiccatum), fragile, chambered (with up to 8 chambers). Context brittle, white to cream, pale orange near the pellis, unchanging; taste mild, pleasant; smell pleasant to fruity. Latex not abundant, white, unchanging; taste mild. Spore-depo­sit white. – Pl. 18

 

Chemical reactions. Context pale salmon pink with FeSO4, changing yellow then olive brown with KOH, yellow with NH4OH, unchanging with HCl and gaiac.

 

Basidiospores ellipsoid, (7.4–)7.5–8.0–8.4–9.6 × 5.9–6.0–6.5–7.3 mm (Q = 1.17–1.23–1.27–1.33; n = 40); ornamentation faintly amyloid, composed of small warts and low ridges forming an obscure broken reticulum; prominences extremely low and hardly distinct; plage inamyloid. Basidia 45–65(–70) × 8–10(–11) mm, cylindrical to slightly clavate, 4-spored, sometimes 2-spored. Pleurocystidia 60–70 × 12–15 mm, clavate, slightly thick-walled. Pleuropseudocystidia not abundant, 3–5 mm, cylindrical, obtuse. Lamellar edge sterile; marginal cells 20–80(–150) × 5–8 mm, cylindrical, obtuse, septate, sometimes branched. Hymenophoral trama composed of small sphaerocytes and hyaline narrow hyphae; laticiferous hyphae not abundant. Pileipellis a trichoderm, composed of interwoven and ascending hyphae, up to 150 mm, hyaline, 4–7 mm diam., with rounded apex, septate, thin-walled. Stipitipel­lis as pileipellis but less thick (up to 70 mm thick). Clamp-connections absent, although in the stipitipellis some clamp-connections-like structures were observed; they are not more frequent towards the base but best observed halfway the stipe. – Fig. 55

 

Ecology. Found in Zambezian miombo woodland dominated by Brachystegia utilis, Sudanian rivulet associated woodland with dominance of Uapaca somon, Uapaca bojeri woodland.

 

Distribution. Widespread in tropical African woodlands. Known from Benin, Burundi, Madagascar and Zimbabwe.

 

Revised specimens

Benin. Atacora Prov., Kota, 23 Sept. 2000, A. De Kesel 2928 (BR 129139–32).

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, 18 May 1993, B. Buyck 5175 (PC); Ibid., 11 Feb. 1994, B. Buyck 5470 (PC); Ibid., 11 March 1994, A. Verbeken 94-063 (BR 57574–53, holotype; GENT, isotype); Ibid., 31 March 1994, A. Verbeken 94-513 (BR 57683–65); Nkayamba, just N of Rumonge, 29 Jan. 1992, B. Buyck 4180 (PC); Ibid., 29 April 1992, B. Buyck 4398 (PC).

Madagascar. Arivonimamo, 30 Jan. 1997, B. Buyck & al. 97-060 (PC).

Zimbabwe. Manicaland Prov., Chipinge, Busi farm, forest around Scott’s house, 12 Feb. 1999, A. Verbeken 99-186 (GENT); Manicaland Prov., Penhalonga, hill behind Harris’ garden, 9 Feb. 1999, A. Verbeken 99-152 (GENT).

 

Notes. This species is characterized by a lot of outstanding and unique characters, not observed in any other African Lactarius species: the bright orange lamellae, the white and fimbriate lamellar edge, the zoned pileus, the very pruinose pileus and the chambered, tapering stipe.


Sect. Rubroviolascentini (Singer) Verbeken

 

Lactarius sect. Rubroviolascentini Verbeken, Mycotaxon 66: 380 (1998). Lactarius subsect. Rubroviolascentini Singer, Ann. Mycol. 40: 114 (1942).

Type species: Lactarius rubroviolascens R. Heim.

 

Notes. The distinction between this section and L. sect. Pseudogymnocarpi is only based on blackening context. This grouping is artificial but maintained for practical reasons.

 

Key to tropical African species

 

1.  Pileus brownish ochre to orange reddish; context becoming blackish, then reddish; spores extremely lowly ornamented to almost smooth; plage not amyloid ..........  32. L. rubroviolascens

     Pileus pale buff; context becoming red, then lilac and finally strongly blackening by the latex; spores with a distinct incomplete reticulum, plage centrally amyloid .............  33. L. denigricans

 

Species descriptions

 

32. Lactarius rubroviolascens R. Heim

Heim, Candollea 7: 377 (1938). – Type: Madagascar, South of Soanierana, near Manompana, 9 Dec. 1934, R. Heim G85 (PC, holotype).

 

Selected descriptions and icons. R. Heim, Prodr. Fl. Mycol. Madagascar 1: 4649 & Pl. 1c (1938); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 138139 & Pl. 6468 (1996d).

 

Pileus 60–80 mm diam., firm, fleshy, first convex and with slight central depression, then planoconvex to irregular; margin inflexed, irregularly crenulate; pellis dehiscent, thick, tomentose (handlens), smooth or with local small excavations, brownish ochre with orange tinge, pale pinkish, greyish pink, slightly hygrophaneous, greyish tinges more obvious when dry, more orange-reddish when wet, sometimes with some blackish spots, often with local whitish pruinose aspect. Lamel­lae broadly adnate to subdecurrent, une­qual with lamellulae of two different lengths, very dis­tant (L+l = 6 to 11/cm), large (7–8 mm), very thick, brittle or papery, cream to slightly greyish yellow (3A2), in some specimens at first blackening, finally violet-blue; edge concolorous or distinctly pale orange (especially in young specimens). Stipe 30–45 × 18–28 mm, cylindrical, slightly tapering downwards, dry, velvety, orange to yellow with pinkish tinge (5A5–6), orange-like near the apex, pale in the middle, brownish orange in the lower part, white and tomentose at the base, sometimes greyish or pinkish at base, solid, firm. Context firm, white, pale orange under the stipitipellis, becoming blackish then reddish in the pileus, or first pale grey, then pink-reddish and finally greyish black, in some specimens unchanging, unchanging in the stipe; taste mild; smell not particular. Latex abundant, water-like, almost translucid, or first white, then heterogenous watery with white clouds, with greyish pink tinge, unchanging or reddening, drying greyish black; taste mild. Spore-depo­sit white. – Pl. 19

 

Chemical reactions. Context unchanging with gaiac and gaiacol; pink with FeSO4; pale lilac with pyramidon. Pileipellis green with FeSO4. (According to Heim 1938b).

 

Basidiospores ellipsoid, (7.7–)8.2–8.89.4–10.3 × 6.3–6.97.4–7.9 mm (Q = 1.20–1.271.28–1.40; n = 50); ornamentation not very distinct, very low and irregular; composed of some irregularly shaped and sized warts and connective lines; plage inamyloid. Basidia 40–60 × 8–11 mm, cylindrical to slightly flexuous or slightly subclavate, 4-spored; sterigmata 5–7 × 1–2(–3) mm. Pleurolamprocystidia very abundant, 110–140 × 10–15 mm, very emergent (up to 70 mm), cylindrical to setiform, obtuse or tapering upwards; wall thickened (1–3(–4) mm); content sometimes granular. Pleuropseudocystidia scarce, (2–)4–6 mm diam.; cylindrical, obtuse, sometimes mucronate, sometimes branched; content oleiferic. Lamellar edge without distinct cells, with some lamprocystidi­a and a lot of dark brown, amorphous flocks. Hymenophoral trama irregular and heteromerous, composed of delicate, hyaline hyphae (3–6 mm diam.) and numerous sphaerocytes; lactifers abundant. Pileipellis a palisade to trichopalisade; suprapellis 50–90 mm thick; subpellis 20–30 mm thick; elements of suprapellis 20–50(–90) × 4–6 mm, cylindrical and obtuse to tortuose, septate and branched, with slightly thickened wall and slightly granular content; subpellis pseudoparenchymatous, with isodiametric or irregular cells. Stipitipel­lis a lamprotrichoderm to lamprotrichopalisade, 100–150 mm thick; elements of the suprapellis resembling the lampropleurocystidia, (50–)100–135 × 4–8 mm, cylindrical to setiform, slightly flexuous, obtuse; wall thickened (1–3 mm); content granular; elements at the base of stipe with remarkable globose and swollen apex; subpellis pseudoparenchymatous, rudimentary; isodiametric cells scarce. Clamp-connections absent. – Fig. 56

 

Ecology. Found in various forest types, such as lowland rainforest, miombo woodland, Uapaca bojeri woodland, dry evergreen forest (muhulu), lowland rainforest. Not common.

 

Distribution. Known from Cameroon, Democratic Republic of Congo, Madagascar, Malawi and Zambia.

 

Revised specimens

Cameroon. Western Prov., near Mundeba, Korup National Park, transect P, 1984, I. Alexander 13 (E).

Democratic Republic of Congo. Shaba Prov., Kipopo, March 1971, D. Thoen 4635 (BR 66235–81).

Madagascar. Betsimisaraka Prov., South of Soanierana, Dec. 1934, R. Heim G85 (PC, holotype); Arivonimamo, 5 Feb. 1997, B. Buyck & al. 97-266 (PC).

Malawi. Northern Prov., Mzimba distr., Mtanga tanga forest, 15 March 2005, F. Noe 05/550 (GENT); Ibid., Perekezi forest reserve, 28 Jan. 2005, A. Verbeken 05-086 (GENT); Ibid., 15 Feb. 2005, F. Noe 05/324 (GENT).

Zambia. Miputu, 22 Jan. 1996, B. Buyck & G. Eyssartier 96-153 (PC); n.l., Feb. 1996, B. Buyck & G. Eyssartier 96-292a (PC).

 

Notes. The type-specimen is conserved in alcohol and consists of one basidiome in rather good condition. The type-material was also studied by Lalli & Pacioni (1992) who excluded the species from Lactarius section Lactifluus.

     The macroscopical description is adapted from Heim (1938b), supplemented with our field notes from Malawi. The microscopic description is based on both Heim G85 and Thoen 4635. The spores of Alexander 13 are somewhat more heavily ornamented.

     An edible species according to Zeller (1982).

 

33. Lactarius denigricans  Verbeken & Karhula

Verbeken, Persoonia 16: 219 (1996). Type: Tanzania, Lirondo, Songea distr., 30 Jan. 1993, Saarimäki & al. 1467 (H, holotype).

 

Selected descriptions and icons. Verbeken, Persoonia 16: 219222 (1996); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 127128 & Pl. 4144 (1996d); Karhula & al., Karstenia 38: fig. 11 (1998); De Kesel & al., Guide des champignons comestibles du Bénin: 171 (2002); Härkonen & al., Norrlinia 10: 83 (2003).

 

Pileus 60–80 mm diam., convex to slightly depressed; margin irregular; pellis mat, slightly wrinkled, pale buff, becoming brownish grey to black when bruised. Lamel­lae decurrent, unequal with mostly short lamellulae, close, large (8 mm), rather thick, ivory coloured, blackening when bruised; edge entire and concolorous. Stipe 45–60 × 15–20 mm, cylindrical, round to applanate on section, mat, longitudinally wrinkled to grooved, pale buff, becoming brownish grey when bruised. Context in the pileus white, becoming red, then lilac and finally black by the latex; in the stipe white, then yellow, red under the surface; taste mild, smell absent. Latex abundant, transparent-whitish, changing red when exposed, finally black; taste mild. Spore-depo­sit not observed.Pl. 20

 

Basidiospores subglobose to ellip­soid, 6.8–7.7–8.4(–8.7) × 5.6–6.3–7.1 mm (Q = 1.12–1.21–1.32; n = 50); ornamentation amyloid, low, up to 0.5 mm high, composed of irregular knotty warts and fine connective lines, never forming a complete reticulum; plage distinct, with a central amyloid spot. Basidia (38–)40–45(–47) × 7–9(–10) mm, cylindrical to slightly clavate, 4-spored; sterigmata 5–7 × 1–2 mm. Pleurolamprocystidia abundant, emergent, 60–135 × 10–11 mm, cylindrical to narrowly fusiform, rounded with thickened wall (1–2 mm). Pleuropseudocystidia not abundant, cylindrical, 7–8 mm diam.; content brownish oleiferic. Lamellar edge heterogenous, composed of lamprocystidia, basidioles and basidia. Hymenophoral trama composed of sphaerocy­tes and abundant broad laticiferous hyphae. Pileipellis a lampropalisade; suprapellis 30–60 mm thick; subpellis 40–50 mm thick; elements of suprapellis 15–55 × 7–8(–10) mm, cylindrical, sometimes clavate, sometimes septate, thick-walled (0–1 mm); subpellis thin, pseudoparenchymatous; spherical cells 5–15 mm. Stipitipel­lis a lamprotricho­derm; 90–140 mm thick; hyphae interwoven and ascending in the suprapellis; no spherical cells; terminal elements cylindrical to slightly tortuous, (10–)25–60(–80) × 6–8(–10) mm, thick-walled (1–2 mm). Clamp-connections absent. – Fig. 57

 

Ecology. Found in miombo woodland with mainly Uapaca and some Brachystegia, and Sudanian rivulet forest dominated by Uapaca somon.

 

Distribution. Known from Benin and Tanzania. Widespread but apparently rare.

 

Revised specimens.

Benin. Atacora Prov., Kota, 17 June 2000, A. De Kesel 2825 (BR 126378–84).

Tanzania. Southern Prov., Songea distr., Lirondo, 30 Jan. 1993, T. Saarimäki 1467 (H, holotype).

 

Notes. This striking species differs from any other species in the section by its colour-change of context and latex. The microscopic characters make it fit very well in Lactarius section Pseudogymnocarpi: emergent and abundant lamprocystidia, hymenophoral trama composed of sphaerocytes, pileipellis-structure a regular lampropalisade, spore-ornamentation an almost complete reticulum and the plage with a central amyloid spot. There are some resemblances with Lactarius rubroviolascens by the colour-changes, the macroscopic aspect of the pileus and the very emergent and abundant lamprocystidia, but the latter species differs in spore-ornamentation and pileipellis-structure.


Sect. Pseudogymnocarpi  Verbeken

 

Lactarius sect. Pseudogymnocarpi Verbeken, Mycotaxon 66: 376 (1998).

Type species: Lactarius gymnocarpoides Verbeken.

 

Key to tropical African species

 

1.  Pleurocystidia abundant and emergent ....................................  2

   Pleurocystidia present but inconspicuous, not emergent; stipe and lamellae remarkably yellow to greenish yellow ....................... 40. L. luteopus

 

2.  Spores on average 12 µm long, 9 µm broad; pileus < 30 mm diam., with a striking carmine red colour ....... 39. L. carmineus

     Pileus differently coloured, spores smaller ...............................................  3

    

3.  Pileus becoming whitish pruinose when older; gill edge orange or brownish; elements of the pileipellis very elongate, up to 300 mm long .......................................................  38. L. medusae

     Pileus not whitish pruinose; gill edge concolorous; elements of the pileipellis up to 100 mm long ............ 4

 

4.  Stipe white, contrasting with orange pileus .........................................................................................  5

     Stipe pale orange to pale yellow, more concolourous with pileus ..................................................  6

 

5.  Spores elongate, average Q = 1.33–1.60; cap up to 7 cm diam., hymenophoral trama with sphaerocytes .... 36. L. longisporus

     Spores ellipsoid, average Q = 1.20–1.27; cap < 3 cm diam., hymenophoral trama lacking sphaerocytes ..... 37. L. pumilus

 

6.  Lamellar edge fertile; ornamentation of the spores composed of an incomplete reticulum without distinct warts .......................... 34. L. gymnocarpoides

    Lamellar edge sterile; ornamentation of the spores composed of a partial reticulum and some isolated warts ................................   35. L. pseudogymnocarpus

 

Species descriptions

 

34. Lactarius gymnocarpoides Verbeken

Verbeken, Mycotaxon 55: 530 (1995). − Type: Burundi, Rumonge, Nkyamba, 15 March 1994, A. Verbeken 94-150 (BR 57604–83, holotype; GENT, isotype).

     Misappl.: Lactarius phlebophyllus ss. Morris (1990).

 

Selected descriptions and icons. Verbeken, Mycotaxon 55: 530533 (1995); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 126127 & Pl. 2840 (1996d); Karhula & al., Karstenia 38: fig. 5 (1998); De Kesel & al., Guide des champignons comestibles du Bénin: 164 (2002); Härkonen & al., Norrlinia 10: 86 (2003).

 

Pileus (40–)60–90 mm diam., quite thick, planoconvex to slightly depressed and infundibuliform; margin incurved when young, then irregular to crenulate and even undulate, sometimes grooved; pellis not dehiscent, dry, smooth to finely felty, wrinkled to cracking, greyish orange to orange when young (6B5–6), then rather light orange (5A4 to 5B4–6). Lamel­lae decur­rent, unequal with lamellu­lae (1 to 3 between 2 lamellae, regular pattern), dis­tant (L+l = 2+3 to 3+6/cm), medium broad ((3–)5–7 mm), thick, brittle, with remarkable venation when older, yello­wish white to pale yellow (3A2–3 to 4A2 to 4B4); edge entire, conco­lo­rous. Stipe 25–65 × 10–20 mm, cylindrical to fusiform, tapering down­wards, exceptionally clavate, dry, smooth, yellowish white to light yellow (4A2–5) or light orange (5A3–5), solid to chambe­red and broadly fistulous. Context firm, white; taste mild to bitter; smell pleasant. Latex not abundant (very abundant in Verbeken 94-644), fluid, white, unchan­ging, mild to astringent. Spore-depo­sit white. – Pl. 21

 

Chemical reactions. Context salmon pink to greyish pink with FeSO4; pale yellow with KOH; unchanging with HCl and NH4OH. Pileipellis olive green (4C5) with KOH.

 

Basidiospores ellipsoid, 8.2–8.9–9.3–10.3 × 6.6–7.2–7.9–8.9 mm (Q = 1.07–1.17–1.27–1.43; n = 120); ornamentation amyloid, forming an almost comple­te reticulum with rather big meshes which become smaller on adaxi­al side; prominences very low (< 0.2 mm high); plage diffusely amy­loid. Basidia 50–70 × 5–13 mm, clava­te, 4-spored. Pleurolamprocystidia abundant, 80–130 × 8–12 mm, fusiform, thick-walled (up to 1.5 mm). Pleuropseudocystidia abundant, 3–5(–7) mm, cy­lin­drical, with rounded apex. Lamellar edge fertile; basidia 37–40 x 9 µm; marginal cells also present, slightly thick-walled, sometimes septate, 40–50 x 8–10 µm. ­­Hymenophoral trama compo­sed of sphaero­cy­tes; laticiferous hyphae present but not very con­spicuous. Pilei­pellis a lampropalisade; elements of the suprapellis 20–60 × 4–11 mm, regularly cylindrical, with sligh­tly thickened wall (0.5–1 mm); subpellis pseudoparen­chymatous, spherical cells (7–)10–20(–30) mm, with slightly thickened wall. Stipiti­pel­lis a trichopalisade, composed of densely interwoven hyphae with terminal elements forming a suprapellis; terminal elements 15–30 × 4–8 mm, cylindrical, someti­mes clavate, thin-walled. Clamp-connecti­ons absent. – Fig. 58

 

Ecology. Widespread in tropical Africa, particularly common in Sudanian woodland and drier miombo woodland; also collected in Uapaca bojeri woodland, dry coastal forest, rainforest, riparian forest, semi‑evergreen forest.

 

Distribution. Known from Benin, Burundi, Democratic Republic of Congo, Guinea, Madagascar, Malawi, Senegal, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Benin. Borgou Prov., Wari Maro, 20 Aug. 1997, A. De Kesel 1949 (BR 74940–56); Ibid., 21 Aug. 1997, A. De Kesel 1950 (BR 74941–57); Ibid., 20 June 1998, A. De Kesel 2162 (BR 112673–56); Ibid., 20 Sept. 1998, A. De Kesel 2287 (BR 112780–66); Ibid., 21 Sept. 1998, A. De Kesel 2292 (BR 112785–71); Ibid., Borgou, 22 Sept. 2000, A. De Kesel 2915 (BR 129126–19). Atacora Prov., Kota, 23 Aug. 1997, A. De Kesel 1986 (BR 74838–51); Kounagnigou, 3 Sept. 1997, A. De Kesel 2044 (BR 74877–90); Ibid., 5 Sept. 1997, A. De Kesel 2062 (BR 74895–11); Kouandé, 25 Sept. 2000, A. De Kesel 2941 (BR 129152–45); Bassila, 4 Oct. 2000, A. De Kesel 3001b (BR 129213–09); Ibid. Boukombé, 2 Aug. 1996, A. De Groote 9 (BR 16652472).

Burundi. Bururi Prov., Nkayamba, near Rumonge, March 1994, A. Verbeken 94-149 (BR 57603–82) & 94-150 (BR 57604–83, holotype); Ibid., April 1992, B. Buyck 4380, 4549 & 4551 (all PC); Ibid., Nov. 1992, B. Buyck 4629, 4630 & 4631 (all PC); Ibid., Dec. 1992, B. Buyck 4747b (PC); Ibid., Feb. 1993, B. Buyck 4937 (PC); Nyamirambo, Rumonge Forest Reserve, March 1994, A. Verbeken 94-397 (BR 57657–39), 94-429 (BR 57661–43) & 94-474 (BR 57681–63); Ruyigi Prov., Ruvubu National Park, April 1994, A. Verbeken 94-644 (BR 57712–94), 94-645 (BR 57713–95) & 94-648 (BR 57715–00) ; Cankuzo Prov., Murango, March 1994, B. Nzigidahera 53 & 54 (all PC).

Democratic Republic of Congo. Shaba Prov., Kanduba, 27 March 1986, J. Schreurs 1529 (BR 8291–46).

Guinea. Fouta Djalon Prov., Lébéké­ré, 14 July 1988, D. Thoen 7966 (BR 66847–14).

Madagascar. Ranohira, 60 km in direction Tulear, near TV Antenna, 3 Feb. 2000, B. Buyck & al. 00-1162 (PC); Arivonimamo, 30 Jan. 1997, B. Buyck & al. 97-045a & 97-116 (all PC).

Malawi. Southern Prov., Maloson mountain, 30 Dec. 1981, B. Morris 493 (K(M) 38469); Machinga Forest Reserve, 11 Feb. 1993, Kathumba/Chifunti 23950 (K(M) 38467); Southern Prov., Machinga distr., Liwonde Forest Reserve, 22 Jan. 2005, A. Verbeken 05-011 & 05-112 (all GENT); Ibid., 23 Jan. 2005, A. Verbeken 05-036 (GENT); Northern Prov., Mzimba distr., Perekezi Forest Reserve, 28 Jan. 2005, A. Verbeken 05-097 & 05-106 (all GENT); Ibid., 29 Jan. 2005, A. Verbeken 05-115, 05-116 & 05-144 (all GENT); Mzimba distr., 31 Jan. 2005, A. Verbeken 05-184/187 & 05-191(all GENT).

Senegal. Basse Casamance Prov., National Park of Basse Casamance, 22 Sept. 1986, D. Thoen s.n. (BR 66214–60).

Tanzania. Southern Highlands Prov., Njombe distr., Mbalali, 1 Feb.1993, T. Saarimäki & al. 1508 (H).

Zambia. Copperbelt Prov., Mwekera forest, between Kitwe and Ndola, 21 Jan. 1991, B. Buyck 3491 (PC); Northern Prov., North Luangwa National Park, 25 Jan. 1995, D. Shah‑Smith 163 (K(M) 35509); farm Gibsons, 16 Jan. 1996, B. Buyck & G. Eyssartier 96-061 (PC); road Mpongwe-Lusaka, Mikati, 18 Jan. 1996, B. Buyck & G. Eyssartier 96-098 (PC).

Zimbabwe. Midlands Prov., Mvuma, Central Estates, Beacon Hill section, 19 Feb. 1996, C. Sharp 455/96 (GENT); Ibid., 9 Jan. 1997, C. Sharp 530/97 (BR 60407–73); Ibid., 26 Jan. 1999, A. Verbeken 99-010 & 99-016 (all GENT); Mashonaland East Prov., Bromley, Liemba farm, 1 Feb. 1999, A. Verbeken 99-063 (GENT); Manicaland Prov., along Mutare-Bvumba road, near Prince of Wales Viewpoint, 11 Feb. 1999, A. Verbeken 99-172 & 99-173 (all GENT); Manica­land Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-183 (GENT); Ibid., 12 Feb. 1999, A. Verbeken 99-200 & 99-202 (all GENT).

 

Notes. The macroscopic description is based on notes from Verbeken and Buyck. The microscopic description is based on Buyck 4549, completed with Buyck 4747 and Buyck 4380.

     The species is most closely related to Lactarius longisporus, from which it differs by the coloured stipe and the more ellipsoid spores which are ornamented with a looser reticulum with bigger meshes. Furthermore, the stipitipellis consists of thin-walled terminal elements whereas the terminal elements in the stipitipellis of Lactarius longisporus are thick-walled.

     Lactarius gymnocarpoides is an edible species, locally well appreciated (Buyck 1994, De Kesel & al. 2002, Yorou & De Kesel 2002, Härkonen & al. 2003). It can be found in large quantities, i.e. up to 100kg/ha/y in savannah woodlands with Uapaca togoensis or Isoberlinia tomentosa (Yorou & al. 2002).

 

35. Lactarius pseudogymnocarpus Verbeken

Verbeken, Mycotaxon 55: 523 (1995). − Democratic Republic of Congo, Binga, M. Goossens-Fontana 899 (BR 12324–05, holotype).

     Misappl.: Lactarius gymnocarpus ss. Heim (1955) pro parte, Pegler (1977).

 

Selected descriptions and icons. Heim, Bull. Jard. Bot. Etat Bxl 25: Pl. 2, fig. 1a,ce (1955); Heim, Fl. Icon. Champ. Congo 4: Pl. 13, fig. 1a,c (1955); Pegler, Kew Bull., Addit. Ser. 6: 571572 (1977, as "L. gymnocarpus"); Verbeken, Mycotaxon 55: 523527 (1995); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 120122 & Pl. 2025 (1996d).

 

Pileus 70–140 mm diam., planoconvex and depressed to infundibuliform; margin crenulate and very irregularly lobed when older, striate to grooved (up to 1/3 of the radius), with very fine veins between the grooves; pellis not dehiscent, dry, finely tomentose, with a fine reticulum of gelatinous, sinuous veins, pale yellow, yellowish orange, bright orange to apricot, almost carrot red becoming brownish orange or with brownish or more yellowish spots. Lamel­lae decurrent and extending in longitudinal veins on the stipe, une­qual with lamellulae of three lengths, dis­tant (L+l = 4/cm), broad (up to 12 mm), thick, white to cream (3A3), with brownish or greyish purple spots; edge entire and concolorous. Stipe 45–100 × 10–20 mm, cylindrical, sometimes tapering downwards, somewhat rugose, whitish, pale orange to ochraceous pink downwards, with a brownish orange tomentose base. Context firm, very thin near the outer part of the pileus, white to cream, with brown spots in older specimens; taste mild. Latex not abundant, transparent to white; taste mild. Spore-depo­sit white. – Pl. 22

 

Chemical reactions. Context immediately brown with pyrogalic acid; soon greyish pink with FeSO4; intensely blue green with gaiac; slowly chocolate brown with phenol; pink with sulfovanilline; unchanging with aniline, naphthol, NH3, SF. Hymenophoral trama violently pink with sulfovanilline. (According to Heim 1955a).

 

Basidiospores ellip­soid, (7.1–)7.7–8.49.1–9.9 × 6.0–6.77.0–7.6 mm (Q = 1.08–1.261.29–1.43; n = 50); ornamentation amyloid, composed of a partial reticulum; warts connected by irregular connective lines, some isolated, up to 0.5 mm high; plage weakly amyloid. Basidia 45–80 × 8–10 mm, cylindrical to clavate, 4-spored, slightly thick-walled; content granular. Pleurolamprocystidia abundant, 50–80(–100) × 5–7 mm. Pleuropseudocystidia scarce. Lamellar edge sterile; marginal cells 15–37 × 4–7 mm, cylindrical, ta­pe­ring or obtuse, of­ten sep­ta­te, thick-walled (up to 1.0 mm). ­Hymenophoral trama composed of sphaerocy­tes; laticiferous hyphae present. Pileipellis a lampropalisade; elements of the suprapellis 30–60 × 5–7 mm, regularly cylindrical, obtuse, thick-walled (1–2 mm); subpellis pseudoparenchymatous; spherical cells 10(–20) mm, with slightly thickened wall. Stipitipel­lis a lamprotrichoderm; elements of the suprapellis 20–60 × 5–10 mm, cylindrical, obtuse to slightly tapering upwards, thick-walled (1–2 mm). Clamp-connections absent. – Fig. 59

 

Ecology. Found in lowland rainforest with Isoberlinia, drier Guineo-Congolian rainforest, Sudanian savannah woodland with Isoberlinia.

 

Distribution. Known from Benin, Democratic Republic of Congo and Tanzania.

 

Revised specimens

Benin. Borgou Prov., Wari Maro, 20 June 1998, A. De Kesel 2164 (BR 112675–58).

Democratic Republic of Congo. Equateur Prov., Binga, date unknown, M. Goossens-Fontana 899 (BR 12324–05, holotype); Ibid., June 1942, M. Goossens-Fontana 3001 (BR 12323–04); Kivu Prov., Irangi, April 1972, J. Rammeloo Z244 (GENT).

Tanzania. Tanga Prov., Amani Forest, E. Usambara Mts., Lushoto, 15 April 1968, D. Pegler T497 (K(M) 159502).

 

Notes. The macroscopic description is primarily based on the description of Pegler (1977) completed with fieldnotes from Goossens-Fontana and Rammeloo on the specimens from Democratic Republic of Congo . There is a serious contradiction concerning the taste and smell. Pegler (1977) describes the taste as "mild" and the smell as "none", while Heim mentions a "very acrid" taste and "acrid and pepper-like" smell, based on observations made by Goossens-Fontana. Interpreting organoleptic characters noted by Goossens-Fontana must be done with caution, since her taste was strongly affected by the use of kinin (Heinemann, pers. comm.). The microscopic description is based on Goossens-Fontana 899 & 3001. The spores from Pegler T497 measure 7.4–8.6–9.7 × 5.9–6.7–7.5 mm (Q = 1.17–1.28–1.45).

     Heim (1955a) noticed that there are differences in venation of the pileus and taste of context and latex, between what he calls "la forme guinéenne" and the collections of Goossens-Fontana. The remarkable differences in spore-dimensions and pileipellis-structure, however, make it clear that both "forms" concern different species. Lactarius gymnocarpus has smaller spores (7.1–8.2 × 5.9–6.4 mm) and the elements of the suprapellis of the pileus and the stipe are very irregularly shaped, vary­ing from narrowly cylindrical to broadly fusiform or almost rounded, often tortuous, with thickened wall (1–3 mm). Lactarius pseudogymnocarpus has longer and wider spores (8.4–9.1 × 6.7–7.0 mm) and the elements of the suprapellis of the pileus and the stipe are regularly cylindrical, obtuse, thick-walled (1–2 mm). Despite the macroscopic resemblance of those two species (aspect and colour of the pileus), important microscopic differences, especially the presence of true cystidia in Lactarius pseudogymnocarpus, and the lack of true cystidia in L. gymnocarpus, make them belong to different sections.

 

36. Lactarius longisporus  Verbeken

Verbeken, Mycotaxon 55: 527 (1995). Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 1 April 1994, A. Verbeken 94-557 (BR 57699–81, holotype; GENT, isotype).

     Misappl.: Lactarius gymnocarpus ss. Buyck & Nzigidahera (1996).

 

Selected descriptions and icons. Verbeken, Mycotaxon 55: 527530 (1995); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 124126 & Pl. 3237 (1996d).

 

Pileus 30–75 mm diam., quite thick (20–45 mm), convex to plano­conca­ve and slightly depressed to depressed, when old infundibuliform and irregular; margin incurved when young, then slightly crenulate and sometimes irregularly grooved when older; pellis not dehiscent, dry, mat, smooth to finely felty, wrinkled to cracked, pale orange to greyish orange (5A4 to 6A5–6 to 6B5–6), sometimes greyish red to brownish orange. Lamel­lae decur­rent, une­qual with lamel­lu­lae [3(–5) between 2 lamellae, regular pattern], very dis­tant (L+l = 2+4 to 3+5/cm), medium broad (4–8 mm), thick, very brittle, with remarkable venation when older, whi­te to cream or yello­wish; edge entire, concolo­rous (pale yellow in Buyck 3583). Sti­pe 25–50 × 8–12 mm, cylin­drical, slender, dry, smooth to very finely felty, white, chambered to hollow. Context firm, white to cream; taste mild to bitter; smell Cantharellus-like or absent. Latex not abun­dant, white, unchan­ging; taste mild to bitter. Spore-depo­sit white. – Pl. 23

 

Chemical reactions. Context salmon pink (sometimes nihil) with FeSO4; unchanging with HCl and NH4OH. Pileipellis light brown to greyish brown with KOH (Verbeken 94-520).

 

Basidiospores ellipsoid to strongly elon­gate, 8.4–9.111.4–12.5 × 6.1–6.67.6–8.4 mm (Q = 1.22–1.331.60–1.80, n = 320); ornamentation amyloid, < 0.1 mm high, composed of a dense and regular reticulum (without isolated warts)­; plage dis­tinct, amyloid. Basidia (48–)54–60(–80) × (8–)9–10.5­(–12) mm, cylindrical to clava­te, 4-spored. Pleurolamprocystidia quite abundant, emergent, (55–)70–80(–90) × 8–12 mm, cylindri­cal to narrowly fusiform, with slightly thicke­ned wall (to 1 mm); content slightly granular. Pleuropseudocystidia pre­sent, undistinct, cylindrical, some­times capitate; con­tent oleife­ric. Lamellar edge fertile. Hymenophoral trama composed of sphae­rocytes; laticiferous hyphae present but inconspicuous. Pilei­pellis a lampropalisade; elements of the suprapellis (10–)35–50(–120) × 4–10 mm, cylindrical, tortuous, sometimes bran­ched and septate, thick-walled (1–2 mm); subpellis pseudoparenchymatous; spherical cells (5–)10–25(–35) mm, thick-walled (0.5–1.5 mm). Stipitipellis a lamprotrichopalisade, hyphae inter­woven and ascending in suprapellis; spherical cells scarce; terminal elements very tortuous, sometimes with cork­screw-like curls, 15–45 × 3–4 mm, slightly thick-walled; some terminal elements cylindrical, 25–45 × 4–6 mm; slightly thick-walled (< 1 mm). Clamp-connections absent. – Fig. 60

 

Ecology. Growing in woodlands dominated by ectomycorrhizal trees.

 

Distribution. Known from Benin, Burundi, Democratic Republic of Congo, Kenya, Madagascar, Malawi, Zambia and Zimbabwe.

 

Revised specimens

Benin. Atacora Prov., Kota, 29 Sept. 2000, A. De Kesel 2966 (BR 129213–09).

Burundi, Bururi Prov., Nyamirambo, Rumonge Forest Reserve, March 1994, A. Verbeken 94-019 (BR 57569–48), 94-066 (BR 57577–56), 94-078 (BR 57588–67), 94-101 (BR 57595–74), 94-220 (BR 57628–10), 94-277 (BR 57634–16), 94-278 (BR 57635–17), 94-282 (BR 57636–18), 94-348 (BR 57648–30), 94-430 (BR 57662–44), 94-520 (BR 57690–72), 94-521 (BR 57691–73) & 94-522 (BR 57692–74); Ibid., April 1994, A. Verbeken 94-557 (BR 57699–81, holotype; GENT, isotype); Ibid., Dec. 1993, B. Buyck 5234, 5235, 5299 & 5300 (all PC); Nkayamba, near Rumonge, Dec. 1992, B. Buyck 4675 & 4754 (all PC); Ibid., March 1993, B. Buyck 5044, 5057 & 5139 (all PC); Rubindi, between Kigwena and Nyanza, 16 Apr. 1978, J. Lambinon 78/169 (LG).

Kenya. Coast Prov., Kwale distr., Arabuko-Sokoke Forest Reserve, plot 1, Aug. 1994, M.H. Ivory IV934 (BR 49370–94); Ibid., plot 3, Nov. 1994, M.H. Ivory IV5025 (BR 49369–93).

Democratic Republic of Congo. Shaba Prov., Ruashi, Jan. 1949, D. Soyer 303 (BR 4905–55); Kipopo, Dec. 1959, M.C. Schmitz-Levecq 185 (BR 12298–76).

Madagascar. Ranohira, 60 km in direction Tulear, near TV Antenna, 3 Feb. 2000, B. Buyck & al. 00-1163 (PC); Ambotantihely, N of Ankazobe, sentier botanique, 15 Feb. 2000, B. Buyck & al. 00-1519 (PC).

Malawi. Northern Prov., Mzimba distr., Perekezi forest reserve, 28 Jan. 2005, A. Verbeken 05-101 (GENT); Ibid., 29 Jan. 2005, A. Verbeken 05-119, 05-120 & 05-130 (all GENT); Ibid., 29 Jan. 2005, F. Noe 05/12 (GENT); Ntanga forest reserve, 30 Jan. 2005, A. Verbeken 05-164 (GENT).

Zambia. Copperbelt Prov., Chati-forest, near Kitwe, Dec. 1990, B. Buyck 3135, 3136, 3201, 3202 & 3209 (all PC); Luapala Prov., Samfya, Dec. 1990, B. Buyck 3256, 3278 & 3279 (all PC); Mansa, Kabunda mission, Jan. 1991, B. Buyck 3351 (PC); Western Prov., Mwinilunga, road to Solwezi, Jan. 1991, B. Buyck 3510, 3513 & 3583 (all PC); farm Gibsons, 16 Jan. 1996, B. Buyck & G. Eyssartier 96-062 (PC); Chibuli, 31 Jan. 1996, B. Buyck & G. Eyssartier 96-251, 96-252 & 96-253 (all PC).

Zimbabwe. Midlands Prov., Mvuma, Central Estates, Baru section, 27 Jan. 1999, A. Verbeken 99-034 (GENT); Midlands Prov., Mvuma, Central Estates, south of Beacon hill ridge, 27 Jan. 1999, A. Verbeken 99-022 (GENT); Ibid., 1 Jan. 1997, C. Sharp 504/97 (BR 60404–70); Ibid., 3 Jan. 1997, C. Sharp 516/97 (BR 60406–72); Ibid., 09 Jan. 1997, C. Sharp 535/97 (BR 60408–74); Ibid., 10 Jan. 1997, Sharp 537/97 (BR 60409–75); Bromley, Liemba farm, 3 Feb. 1999, A. Verbeken 99-098 (GENT); Manicaland Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-197 (GENT).

 

Notes. The macroscopic description is mainly based on notes from Verbeken, completed with notes from Buyck. The microscopic description is based on Buyck 5139, 4675, 4754, 3135 & 5235.

     The species is easily recognized by the orange pileus, contrasting with the white stipe and the elongate spores with the ornamentation forming a dense reticulum. Especially in young condition it shares some macroscopic characters with Lactarius pumilus, from which it differs by the much longer spores with a denser reticulum and by the hymenophoral trama, here composed of sphaerocytes, whereas composed of hyphae in L. pumilus.

     In some specimens (Buyck 4754 & 3351) small, irregularly diverticulate elements are observed in the hymenium. It is not clear whether those are cystidia or deformed basidioles.

     This species is locally eaten (e.g. Nzigidahera 1993, Verbeken & al. 2000).

 

37. Lactarius pumilus  Verbeken

Verbeken, Bull. Jard. Bot. Nat. Belg. 65: 205 (1996). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, 1 April 1994, A. Verbeken 94-559 (BR 57702–84, isotype GENT).

 

Selected descriptions and icons. Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 122123 & Pl. 2628 (1996d); Karhula & al., Karstenia 38: fig. 9 (1998); Härkonen & al., Norrlinia 10: 90 (2003).

 

Pileus 10–30 mm diam., firm, fleshy, planoconvex and depressed, rather irregular; margin incurved, irregularly lobate, then crenulate; pellis dry, finely felty, pale orange, greyish orange to brownish orange or reddish blond (5A3 to 5B3 to 5C3). Lamellae slightly decurrent, unequal with 1–3 lamellulae between two lamellae (regular pattern, lamellulae mostly very short), moderately distant (L+l = 4+9/cm), elastic, paper-like, pale yellow to light yellow (4A3–4); edge entire, darker. Stipe 10–25 × 5–10 mm, short cylindrical, dry, finely felty, pale orange to orange white (5A3–4) in upper half, more whitish near the base, firm, solid, sometimes subfistulous. Context firm, white, slightly yellowing when cut or bruised; smell not remarkable; taste mild. Latex scarce, white. Spore-deposit not observed. – Pl. 24

 

Chemical reactions. Context pale orange with FeSO4. Pileipellis dark brown (8F3) with KOH; greyish brown (8D3) with NH4OH.

 

Basidiospores sometimes subglobose, sometimes elongate, mostly ellipsoid, 7.2–8.58.9–9.9(–10.3) × 5.9–6.77.4–8.0(–8.3) mm (Q = 1.12–1.201.27–1.45, n = 40); ornamentation amyloid, composed of narrow, low ridges, forming an incomplete to almost complete reticulum, without isolated warts; plage sometimes with central amyloid spot. Basidia (30–)40–45(–50) × 8–11 mm, subclavate, 4-spored, sometimes 2-spored; content guttate. Pleurolamprocystidia very abundant, emergent, 50–80 × 5–8(–10) mm, cylindrical to subcylindrical, rounded at the apex, rarely constricted and tapering upwards, thick-walled, hyaline or with needle-like content. Pleuropseudocystidia scarce, not emergent, 3–5 mm diam., cylindrical, rounded at the apex; content oleiferic. Lamellar edge sterile; marginal cells 10–25 × 3–5 mm, subfusiform to irregular, sometimes branched, hyaline, thin-walled or slightly thick-walled. Hymenophoral trama irregular, composed of narrow, thin-walled, densely interwoven hyphae and abundant lactifers. Pileipellis a lampropalisade; suprapellis composed of narrow, long, cylindrical elements; terminal elements thick-walled, 10–100 × 3–7 mm, sometimes septate; subpellis pseudoparenchymatous; isodiametric cells thin-walled or slightly thick-walled, 5–15(–20) mm diam. Stipitipellis a layer of ascending, narrow, long, cylindrical elements, thin-walled or slightly thick-walled, 10–100(–200) × 3–5 mm, sometimes septate, remarkably corkscrew-like at the end, originating from a layer of hyaline, thin-walled, recumbent hyphae; no sphaerocytes. Clamp-connections absent. – Fig. 61

 

Ecology. Found in miombo woodland, semi-evergreen forest, riverine woodland, Sudanian savannah woodland with Isoberlina or Afzelia.

 

Distribution. Known from Benin, Burundi, Kenya, Senegal, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Benin. Atacora Prov., Kota, 23 Aug 1997, A. De Kesel 1987 (BR 74839–52); Ibid., 1 Oct 1999, A. De Kesel 2731 (BR 116740–49).

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, 1 April 1994, A. Verbeken 94-559 (BR 57702–84, holotype; GENT, isotype); Nkayamba, just N of Rumonge, 1 March 1993, B. Buyck 5000 (PC).

Kenya. Coastal Prov., Kayatelesi, Shimba Hills, 4 Dec. 2004, A. De Kesel 3977 (BR 16650856).

Senegal. Basse Casamance, 22 Aug. 1987, D. Thoen 7618 (BR 3155–51).

Zambia. Northern Prov., North Luangwa National Park, Mwaleshi Camp, 20 Jan. 1995, D. Shah‑Smith 156 (K(M) 35501); Copperbelt Prov., Chati forest near Kitwe, 15 Dec. 1990, B. Buyck 3137 (PC).

Zimbabwe. Manicaland Prov., Chipinge, Busi farm, around Scott’s house, 12 Feb. 1999, A. Verbeken 99-198 (GENT); Mashonaland East Prov., Bromley, Liemba farm, 2 Feb. 1999, A. Verbeken 99-070 (GENT); Masvingo Prov., south of Lake Mutirikwe, around Norma Jean’s lodge, 16 Feb. 1999, A. Verbeken 99-222 (GENT).

 

Notes. The macroscopic description is based on fieldnotes of Buyck; the microscopic description is based on Buyck 5000 and Verbeken 94-559.

     This is the only species in this group where no sphaerocytes were observed in the trama. In all other characters the species fits well in this section. The species is characterized by the very small and bright orange basidiomes (contrasting with the white stipe). The pileus does not exceed 3 cm in diam.

     This is an edible species (e.g. Karhula & al. 1998).

 

38. Lactarius medusae  Verbeken

Verbeken, Mycotaxon 55: 532 (1995). − Type: Zambia, near Kawambwa, 6 Jan. 1991, B. Buyck 3455 (BR 38489–77, holotype; PC, isotype).

     Misappl.: Lactarius vellereus ss. Morris (1984, 1987, 1990) and Williamson (1975, 1976); Lactarius. latifolius ss. Parent & Thoen (1977); Lactarius gymnocarpus ss. Pegler & Piearce (1980).

 

Selected descriptions and icons. Verbeken, Mycotaxon 55: 532535 (1995); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 123124 & Pl. 2931 (1996d); Karhula & al., Karstenia 38: fig. 10 (1998); Härkonen & al., Norrlinia 10: 89 (2003).

 

Pileus (63–)70–120 mm diam., moderately thick, plano­conca­ve or applanate to sligh­tly depressed; margin irregularly lobulate in old specimens; ­pellis not dehiscent, velutinous, mat, dry, pruinose, concentrically wrinkled, dark orange or pinkish brown, pale yellow to yellowish white (4A2–3) when dried. Lamel­lae subdecurrent, decurrent or adnate, dis­tant (L+l = 4–5/cm), medium broad to broad (3–9 mm), rather thick, cream; edge entire, brown or orange. Sti­pe 40–65 × 12–27 mm, central to eccentric, irregu­larly cylin­drical, slightly tapering downwards, smooth, pruinose and wrinkled at the base, reddish blond to brownish orange (5C4), darker towards the base. Context brittle, more solid in the stipe, yellowish white to white, orange under the pileipellis; taste mild; smell pleasant, slightly acid. Latex white, changing violet on the context; taste mild. Spore-deposit not observed. – Pl. 25 & 26

 

Basidiospores ellip­soid, 7.5–8.59.2–10.3 × 5.3–6.67.1–7.8 mm (Q = 1.15–1.281.31–1.42; n = 60); ornamentation amyloid, composed of a complete and dense reticu­lum; warts never isolated, up to 0.3 mm high; connective lines narrow; plage distinct, centrally amyloid. Basidia 55–65(–85) × 7–9(–11) mm, cylin­drical to slightly clava­te, 4-spored; content granular. Pleurolamprocystidia abundant, emergent up to 35 mm, 60–80 × 5–6,5 mm, cylindri­cal, with thickened wall (up to 2 mm). Pleuropseudocystidia not abundant, 3–5 mm, cylindrical, obtuse. Lamellar edge steri­le; marginal cells 45–70 × 4–7 mm, cylin­drical to slight­ly cla­va­te; apex obtuse; wall thickened up to 1 mm. ­­­Hymenophoral trama compo­sed of sphaero­cytes; laticiferous and oleife­ric hyphae abundant. Pileipellis a lampropalisade; suprapellis up to 300 mm, elements of the suprapellis extremely long, (20–)80–250 × 3–6 mm, regularly cylindrical, tapering, sometimes branched, with thickened wall (1–2 mm); subpellis pseudoparenchyma­tous, spherical cells (5–)10–20 mm, with slightly thickened wall. Stipitipel­lis a lampropalisade, idem as pileipellis, spherical cells less dis­tinct. Clamp-connections absent. – Fig. 62

 

Ecology. Miombo woodland.

 

Distribution. Known from Democratic Republic of Congo, Malawi, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Democratic Republic of Congo. Shaba Prov., bought by Parent on road to Likasi, March 1973, D. Thoen 5741 (BR 66366–18).

Malawi. Northern Prov., 3 miles E of Mzuzu, Katoto, March 1973, J. Williamson 629 (K(M) 34216); Southern Prov., Mulanje distr., Mulanje mountains, Likabula Valley, 12 March 1973, L. Ryvarden 11507 (K(M) 38472); Makwawa, Zomba distr., March 1980, B. Morris 110a (K(M) 159574); Northern Prov., Mzimba distr., Ntanga Forest Reserve, 30 Jan. 2005, A. Verbeken 05-145, 05-149 & 05-153 (all GENT); Ibid., Mtanga tanga forest, near Chicangana village, 19 Feb. 2005, F. Noe 05/400-411 (all GENT); Ibid., Perekezi Forest Reserve, 29 Jan. 2005, A. Verbeken 05-114 (GENT); Ibid., Mzimba distr., 31 Jan. 2005, A. Verbeken 05-181 (GENT).

Tanzania. Southern Highlands Prov., Njombe distr., Mbalali, 1 Feb. 1993, T. Saarimäki & al. 1502 (H); Iranga distr., Sao Hill Sawmills, 29 March 1991, T. Saarimäki & al. 763 (H); Iranga distr., Mafinga, 6 Feb. 1993, T. Saarimäki & al. 1589 (H).

Zambia. Luapala Prov., near Kawambwa, 6 Jan. 1991, B. Buyck 3455 (BR 38489–77, holotype; PC, isotype); Northern Prov., North Luangwa National Park, Mwaleshi Camp, 15 Feb. 1995, D. Shah‑Smith 236 (K(M) 35505); road Mpongwe to Lusaka, 18 Jan. 1996, B. Buyck & G. Eyssartier 96-099 (PC); Copperbelt Prov. Kitwe, 21 Dec. 1978, G. Piearce FP600/1c (K(M) 38494).

Zimbabwe. Manicaland, Vuma, Chinziwa Mountain, 24 Jan. 2006, C. Sharp 1788 (GENT); n.l., Feb. 1999, D. Arora 99-112 (SFSU).

 

Notes. The macroscopic description is mainly based on fieldnotes of Saarimäki & al. The microscopic description is based on Buyck 3455.

     Small, irregularly diverticulate elements are observed in the hymenium (Buyck 3455). It is not clear whether those are cystidia or deformed basidioles.

     The species is easily recognized by the pruinose and velutinous pileus, the coloured lamella edge, and microscopically by the very long terminal elements in the pileipellis.

     Lactarius medusae is a well appreciated edible milk cap (e.g. Karhula & al. 1998, Morris 1984).

 

39. Lactarius carmineus  Verbeken & Walleyn

Verbeken & al., Syst. Geogr. Pl. 70: 190 (2000). – Type: Zimbabwe, Mashonaland East, Bromley, Liemba farm, 3 Feb. 1999, A. Verbeken 99-099 (GENT, holotype).

 

Selected descriptions and icons. Verbeken & al., Syst. Geogr. Pl. 70: 190192 (2000).

 

Pileus 13–30 mm diam., planoconvex to almost applanate, with an undeep depression and often an irregular papilla; pellis velvety in very young specimens, later still a bit velvety in center, but rugose towards margin, carmine (10F8, “violet brown”) with paler margin (10E8) in young material, later reddish brown to carmine (9E8 to 8D8), brownish orange (6C4) towards margin; margin striate almost up to center, sulcate with deep and broad grooves. Lamellae very distant (L+l = 14–16/half of the pileus), sometimes forked, with abundant lamellulae (short ones, without regular pattern), decurrent in older specimens, adnate in younger material, pale orange (5A3), with irregular venations in between. Stipe 10–30 × 3–6 mm, irregularly cylindric, smooth, brownish orange, greyish orange, pale orange (6B6–7 to 6C6–7 to 6B4 or 6A3), very brittle. Context very brittle, thin-fleshed in pileus, with abundant chambers in the stipe, whitish; taste mild; smell not remarkable. Latex watery white, unchanging with KOH. Spore-deposit not observed. – Pl. 26

 

Chemical reactions. Context slightly greyish with FeSO4, unchanging with gaiac.

 

Basidiospores ellipsoid, 11–12.1–13.4 × 8.1–9.0–9.8 µm (Q = 1.24–1.34–1.50, n = 20); ornamentation amyloid, composed of irregular, mostly elongated warts of 0.2 µm high, aligned or connected and forming a very incomplete but extremely dense reticulum; plage not amyloid. Basidia 55–70 × 12–15 µm, subclavate, 4-spored, thin- or thick-walled (1–2 µm); some 1-spored or deformed basidia present. Pleurolamprocystidia abundant, emergent, 100–120 × 10–12 µm, very thick-walled (2–3 µm), lanceolate. Leptocystidia (deformed basidioles) present, 20–30 × 6–8 µm, thin-walled, hyaline, with diverticulate knobs. Pleuropseudocystidia scarce, not emergent. Hymenophoral trama cellular. Lamellar edge sterile; marginal cells very irregularly shaped, with diverticulate knobs, hyaline, thin-walled. Pileipellis a lampropalisade, 100–150 µm thick; terminal elements cylindric or slightly irregular, with rounded apex, 25–80 × 5–10 µm, thick-walled, often septate; subpellis composed of rather small (5–10 µm diam.) and thin-walled globose cells. Stipitipellis a lamprotrichoderm; terminal elements slightly to clearly thick-walled, 20–80 × 4–8 µm. Clamp-connections absent. – Fig. 63

 

Ecology. Drier Zambezian miombo woodland.

 

Distribution. Only known from Zimbabwe and Malawi.

Revised specimens

Malawi. Northern Prov., Mzimba distr., Ntanga Forest Reserve, 30 Jan. 2005, A. Verbeken 05-146 (GENT).

Zimbabwe. Mashonaland East Prov., Bromley, Liemba farm, Carters estates, 3 Feb. 1999, A. Verbeken 99-099 (GENT, holotype).

 

Notes. The species is recognized by the striking carmine to reddish brown cap-colour (especially in young specimens) and the large spores, some of the largest known in African Lactarius species.

     In the Malawian material we observed some mature basidia at the lamella edge.

 

40. Lactarius luteopus Verbeken

Verbeken, Mycotaxon 55: 536 (1995). − Type: Burundi, Rumonge Forest Reserve, Nyamirambo hill, A. Verbeken 94-463 (BR 57669–51, holotype; GENT, isotype).

     Misappl.: Lactarius caperatus ss. Morris (1990).

 

Selected descriptions and icons. Verbeken, Mycotaxon 55: 536539 (1995); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 119120 & Pl. 1719 (1996d); Karhula & al., Karstenia 38: fig. 1 (1998); De Kesel & al., Guide des champignons comestibles du Bénin: 172 (2002); Härkonen & al., Norrlinia 10: 88 (2003).

 

Pileus 20–60(–100) mm diam., rather thin (1–3 mm), planoconvex and slightly depressed to infundibuliform and irregularly so, sometimes with a small papilla; margin slightly incurved when young, then irregular to crenulate and even undulate; pellis not dehiscent, dry, smooth, finely wrinkled, especially towards the margin, sometimes cracking, pale yellow to orange yellow (3A4–5, 4A4–8) or deep orange to greyish orange (5A6, 5B5–6); margin paler yellow when young. Lamel­lae decur­rent, unequal with lamellu­lae (1 to 3 between 2 lamellae, regular pattern), dis­tant (L+l = 2+3 to 5+15/cm), medium broad [4–7(–11) mm], thick, very brittle, with remarkable venation when older, vivid yellow when young (4A8), rather pale yellow (4A4) or pale orange (5A5) to even yellowish white (3A2) when older; edge entire, conco­lo­rous. Stipe 10–35(–45) × 6–15(–20) mm, shortly cylindrical, often tapering down­wards, dry, smooth, vividly yellow (23A7–8) to greenish yellow (1A7–8), when paler then always yellow at the base, firm, becoming fistulous. Context fragile, white, vividly yellow around the cavities in the stipe; taste mild, pleasant; smell pleasant, Cantharellus-like. Latex not abundant, white, unchan­ging, mild. Spore-depo­sit white. – Pl. 27

 

Chemical reactions. Context immediately orange or faintly so with FeSO4, unchanging with HCl, KOH, NH4OH.

 

Basidiospores ellip­soid to elongate, 7.3–8.38.9–9.9 × 5.8–6.36.7–7.3 mm (Q = 1.17–1.261.41–1.55; n = 180); ornamentation amyloid, forming an incomplete to almost comple­te, irregular reticulum; isolated warts also present but rare; prominences very low (< 0.2 mm high); plage centrally amy­loid. Basidia 45–60 × 7–10 mm, cylindrical, (2)4-spored. P­leuro­cys­tidia very scarce, not very emergent, cylindrical to narrowly fusiform, often septate, 55–70 × 7–10 mm, with a slightly thickened wall; content granular. Pleuropseudocystidia not abundant, 3–5 mm, cylindrical, obtuse. Lamellar edge fertile. Hymenophoral trama compo­sed of sphaero­cy­tes; laticiferous hyphae present but not very con­spicuous. Pilei­pellis a lampropalisade; elements of the suprapellis 15–70 × 3–6 mm, cylindrical, sometimes branched, sometimes septate, slightly tapering, densely interwoven, with slightly thickened wall, subpellis pseudoparenchymatous. Stipiti­pel­lis a lampropalisade; elements of the suprapellis 25–55 × 4–8 mm, cylindrical, sometimes slightly clavate, thick-walled (up to 1.5 mm); subpellis pseudoparenchy­matous. Clamp-connecti­ons ­absent. – Fig. 64

 

Ecology. Zambezian miombo woodland, Sudanian woodland. Found e.g. under Isoberlinia, Uapaca, Brachystegia.

 

Distribution. Known from Benin, Burundi, Malawi, Tanzania, Zambia and Zimbabwe.

 

Revised specimens

Benin. Atacora Prov., Kota, 23 Aug. 1997, A. De Kesel 1988 (BR 74840–53); Ibid., 29 Aug. 1997, A. De Kesel 2018 (BR 74864–77); Ibid. 7 Jun 2002, A. De Kesel 3310 (BR 152185–89); Ibid. 18 Jun. 2004, A. De Kesel 3694 (BR 157125–82); Donga Prov., Bassila, 4 Oct. 2000, A. De Kesel 3001 (BR 129213–09); Ibid. 25 Jun. 2002, A. De Kesel 3456 (BR 152259–66); Ibid. 17 Jun 2004, A. De Kesel 3665a (BR 157032–86) & 3665b (BR 157034–88); Kikélé, 13 Jun. 2002, A. De Kesel 3396 (BR 152106–10); Pénésoulou, 8 Oct. 2002, A. De Kesel 3543 (BR 152028–29); Borgou Prov., Doguè, 10 Oct. 2001, A. De Kesel 3210 (BR 149716–45); Wako, 11 Sep. 2001, A. De Kesel 3136 (BR 149795–27); Wari Maro, 20 Jun. 1998, A. De Kesel 2159 (BR 112670–53); Ibid., A. De Kesel 2160 (BR 112671–54); Ibid., 21 Sept. 1998, A. De Kesel 2290 (BR 112783–69); Ibid., 22 Sept. 2000, A. De Kesel 2914 (BR 112783–69).

Burundi. Bururi Prov., Nyamirambo, Rumonge Forest Reserve, March 1994, A. Verbeken 94-347 (BR 57647–29), 94-428 (BR 57660–42), 94-463 (BR 57669–51, holotype; GENT, isotype) & 94-464 (BR 57670–52); Nkayamba, near Rumonge, Dec. 1992, B. Buyck 4807 (PC); Mugara, 18 Nov. 1978, J. Rammeloo 5785 (BR 8768–38).

Malawi. Southern Prov., Makwawa, Zomba, April 1991, B. Buyck 3976 (PC); Zomba distr., near R.C. Cathedrale, 9 Jan. 1974, J. Williamson 768 (K(M) 38484); Central Prov., Lilongwe distr., Bunda, 26 Jan. 1972, J. Williamson 581 (K(M) 38475); Southern Prov., Machinga distr., Liwonde Forest Reserve, 23 Jan. 2005, A. Verbeken 05-047 (GENT); Northern Prov., Mzimba distr., Perekezi Forest Reserve, 28 Jan. 2005, A. Verbeken 05-081 & 05-100(all GENT); Ibid., 29 Jan. 2005, A. Verbeken 05-117 & 05-118 (all GENT); Mzimba distr., Ntanga Forest Reserve, 30 Jan. 2005, A. Verbeken 05-148 (GENT); Ibid., 31 Jan. 2005, A. Verbeken 05-174 (GENT).

Tanzania. Southern Prov., Songea distr., Mawa, 27 Jan. 1993, T. Saarimäki & al. 1415 & 1424 (all H); Songea distr., Hanga, Nyamagoma, 27 Jan. 1993, T. Saarimäki & al. 1432 (H); Southern Highlands Prov., Njombe distr., Ngaramira, 31 Jan. 1993, T. Saarimäki & al. 1486 (H); Mbalali, 1 Feb. 1993, T. Saarimäki & al. 1504 (H); Lake Prov., Bitarambo distr., Bwanga Research Station, 4 Jan. 1973, D.L. Ebbels F14 (K(M) 38488).

Zambia. Luapala Prov., Samfya, Dec. 1990, B. Buyck 3252, 3270, 3272, 3281, 3282 & 3285 (all PC); Mansa, Kabunda mission, Dec. 1990, B. Buyck 3286 & 3287 (all PC); Copperbelt Prov., Misaka Forest Reserve, Dec. 1982, G. Piearce FP731/3 (K(M) 38499); road Mpongwe-Lusaka, Mikati, 18 Jan. 1996, Buyck & Eyssartier 96-097 (PC); farm Gibsons, 20 Jan. 1996, B. Buyck & G. Eyssartier 96-145 (PC); Lusaka, near airport, 11 Feb. 1996, B. Buyck & G. Eyssartier 96-350 (PC).

Zimbabwe. Midlands Prov., Mvuma, Central Estates, along road to Kwekwe, 15 Feb. 1999, A. Verbeken 99-217 (GENT); Mashonaland Central Prov., Mazowe Botanical Reserve, 16 Feb. 1988, L. Ryvarden 25091 (GENT).

 

Notes. The macroscopic description was based on fieldnotes from Buyck and Verbeken. The microscopic description was adapted from Buyck 3281 & 3286.

     A 5-spored basidium was observed in Buyck 3281.

     In Rammeloo 5785 small, irregularly diverticulate elements are observed in the hymenium. It is not clear whether those are cystidia or deformed basidioles.

     The species is easily recognized in the field by the vividly yellow stipe and vividly yellow young lamellae. It differs from the other species in the section by the scarce, not emergent true cystidia, but is nevertheless classified in Lactarius section Pseudogymnocarpi given the other microscopic and macroscopic characters.

     This is an edible species (e.g. De Kesel & al. 2002, Yorou & al. 2002, Karhula & al. 1998). 


Sect. Rugati  Verbeken

 

Lactarius sect. Rugati (Pacioni & Lalli) Verbeken, Mycotaxon 66: 372 (1998). Lactarius subsect. Rugati Lalli & Pacioni, Mycotaxon 44: 190 (1992).

Type species: Lactarius rugatus Kühner & Romagn.

 

Key to tropical African species

 

1.  Pileipellis with orange tinges, rather tomentose, not veined or wrinkled, at most slightly wrinkled; stipe short compared to pileus diameter ........................................................................................  2

     Pileipellis with reddish brown tinges, finely but distinctly veined and wrinkled or cracking; stipe longer (3–8 cm) ......... 3

           

2.  Lamellae pure white and contrasting with the orange to yellowish orange stipe and pileus ..... 41. L. volemoides

     Lamellae orange ................................ 42. L. pseudovolemus

 

3.  Lamellae dense, cap often cracking ...................................................................  45. L. xerampelinus

     Lamellae (moderately) spaced, not cracking ...........................................  4

 

4.  Pileus orange-red to brown; spores 9 × 6.5–7 mm; warts small, mostly elongate and up to 0.1 mm high; elements of stipitipellis (20–)50–100 ´ 4–6 mm, thick-walled, extremely long and tortuous at the base of the stipe .......  43. L. rubiginosus

     Pileus dark brown when young, then paler and more reddish, sometimes with ochraceous spots; spores smaller, 7.9–8.4 ´ 5.9–6.3 mm, warts more rounded, up to 0.2 mm high; elements of the stipitipellis 10–40 ´ 2–4 mm, thin-walled, only thick-walled at the base ........ 44. L. kivuensis

 

Species descriptions

 

41. Lactarius volemoides Karhula

Karhula & al., Karstenia 38: 53 (1998). − Type: Tanzania, Mbeya distr., Mbozi, 24 March 1991, T. Saarimäki & al. 705 (H, holotype).

 

Selected descriptions and icons. Karhula & al., Karstenia 38: 5355, fig. 6 (1998); Verbeken & al., Syst. Geogr. Pl. 70: 211 (2000); Härkonen & al., Norrlinia 10: 92 (2003).

 

Pileus 90 mm diam., undulate, slightly depressed; pellis finely velvety, soft, dry, wrinkled and radially wrinkled at the margin, with an irregular surface, deep orange to brownish orange (6B8 to 6C8) in the center, a bit paler and orange (5A6) near margin, orange white to pale orange (5A2–3) at margin; margin irregularly widely crenulate. Lamellae decurrent with tooth, very distant (L+l = 22/half a pileus), rather thick, brittle, pure white; edge entire, concolorous. Stipe 60 × 30 mm, irregularly cylindric, tapering; pellis smooth, glabrous, dry, light yellow to pale orange (4A4 to 5A3), unicolorous except for the upper zone (zone of the lamellae teeth) where the stipe is pure white as the lamellae (a very distinct separation). Context thick and firm but very thin at the margin of the pileus, firm and solid in the stipe, white, unchanging; taste agreeable; smell herb-like, agreeable. Latex rather abundant, white, pale brownish red when drying on the lamellae; taste mild. Spore-deposit not observed. – Pl. 28

 

Chemical reactions. Context slowly blueing with gaiac, salmon with FeSO4.

 

Basidiospores ellipsoid to elongate, 8.5–9.5–10.5 × 6.0–7.0–8.5 µm (Q = 1.15–1.40–1.50); ornamentation amyloid, composed of narrow and low ridges, up to 0.2 µm high, forming a very incomplete reticulum, some very short ridges or irregular elongate warts present; plage centrally amyloid. Basidia 55–75 × 9–11 µm, narrowly cylidric, long and slender, 4-spored; content guttate. Pleurocystidia absent. Pleuropseudocystidia not abundant, not emergent, 3–6 µm diam., cylindric with rounded apex, with refractive oil-like and guttate content. Lamellar edge sterile; marginal cells cylindric, 25–40 × 4–7 µm, hyaline, thin-walled. Hymenophoral trama mixed, composed of hyaline hyphae, sphaerocytes (forming distinct rosettes) and abundant lactifers. Pileipellis a lampropalisade; suprapellis 40–50 µm thick, composed of erected hairs which are 10–50 × 3–6 µm, subcylindric to subfusiform, tapering upwards, often septate; subpellis 60–80 µm, composed of globose cells of 5–30 µm diam. with a slightly thickened wall. Clamp-connections absent. – Fig. 65

 

Ecology. Found in drier Zambezian miombo woodland, Sudanian riverine forest with Uapaca somon.

 

Distribution. Known from Benin, Tanzania and Zimbabwe.

 

Revised specimens

Benin. Atacora Prov., Kota, 29 Aug 1997, A. De Kesel 2019 (BR 74865–78).

Tanzania. Southern Highlands Prov., Mbeya distr., Mbozi, 24 March 1991, T. Saarimäki & al. 705 (H, holotype); Ibid., Mbeya distr., Ipembe Hill, 28 March 1991, T. Saarimäki & al. 749 (H).

Zimbabwe: Midlands Prov., Mvuma, Central Estates, Beacon Hill section, leg. R. Walleyn 27 Jan. 1999, A. Verbeken 99-020 (GENT).

 

Notes. This species is eaten in Tanzania (e.g. Karhula & al. 1998).

 

42. Lactarius pseudovolemus R. Heim

Heim, Candollea 7: 378 (1938). – Type: Madagascar, S of Maningory, 7 Dec. 1934, R. Heim G61 (PC, holotype).

 

Selected descriptions and icons. Heim, Prodr. Fl. Mycol. Madagascar 1: 4951 (1938); Verbeken, Biodiversity of the genus Lactarius Pers. in tropical Africa: 109110 & Pl. 13 (1996d).

 

Pileus 50–60 mm diam., firm, fleshy, thick, convex, then deeply depressed; margin largely incurved; pellis not dehiscent, finely tomentose-granular, dry, orange-brown near the margin, dark brownish red in the centre. Lamellae adnate to decurrent, unequal with lamellulae of different lengths, distant (L+l = 36/total), rather narrow (1.5–3.5 mm), thick, brittle, orange; edge sharp, entire, concolorous. Stipe 30–35 × 8–9 mm, cylindrical, finely tomentose-granular, orange-brown, slightly paler than the pileus, with tough mycelium towards the base, solid; base slightly rooting. Context cream, unchanging, becoming blackish to brownish in alcohol; smell not particular; taste not particular. Latex abundant, white, unchanging; taste mild, a bit astringent. Spore-deposit white. (According to Heim 1938b).

 

Chemical reactions. Context slowly blue-green with gaiac; slowly lilac with gaiacol; slowly purple with pyramidol.

 

Basidiospores ellipsoid, sometimes elongate, 7.0–8.0–9.0 × 5.4–6.0–6.6(–7) mm (Q = 1.24–1.33–1.42, n = 30); ornamentation amyloid, composed of elongated warts, aligned or connected by fine connective lines, seldom isolated, forming an almost complete reticulum, up to 0.2 mm high; plage inamyloid. Basidia 45–50 × 9–10 mm, cylindrical to subclavate, 4-spored, sometimes 2-spored; sterigmata 3–4 × 1–2 mm. Pleurocystidia absent. Pleuropseudocystidia abundant, slightly emergent, (2–)4–7 mm diam., cylindrical, tapering upwards; content oleiferic. Hymenophoral trama with very abundant lactifers. Pileipellis a palisade; suprapellis 40–50 mm thick; subpellis 50–70 mm thick; terminal elements of suprapellis 20–40(–50) × 3–7 mm, cylindrical, 2- or 3-septate, obtuse, with granular content, slightly thick-walled; subpellis pseudoparenchymatous, composed of slightly thick-walled, isodiametric cells, 5–15(–20) mm. Stipitipellis with more slender, long terminal elements, 15–70 × 3–5 mm, cylindrical, obtuse, thin-walled. Clamp-connections absent. – Fig. 66

 

Ecology. Malagasy lowland rainforest.

 

Distribution. Only known from the type locality.

 

Revised specimens

Madagascar. Betsimisarka Prov., south of Maningory, 7 Dec. 1934, R. Heim G61 (PC, holotype).

 

Notes. I traced two exsiccata with the number G61 in PC. One of them (renumbered here as G61bis) consists of small, immature basidiomes, conserved in alcohol and representing most probably Lactarius annulatoangustifolius. The type of L. pseudovolemus consists of one half basidiome in very bad condition. As the material was not in a good condition I did not succeed in studying the lamellar edge and the hymenophoral trama.

     Lactarius pseudovolemus