Cystidia, Hubner, 1819

Rossi, Walter, Das, Kanad, Hembrom, Manoj Emanuel, Santamaria, Sergi, Parihar, Arvind, Ghosh, Aniket, Henkel, Terry W., Hofstetter, Valerie & Randrianjohany, Émile, 2020, Fungal Biodiversity Profiles 91 - 100, Cryptogamie, Mycologie 20 (4), pp. 69-107 : 98-101

99. Russula liberiensis Sing.

( Figs 20-21 )

Papers of the Michigan Academy of Sciences 32: 112 (1948) (for 1946).

ORIGINAL DIAGNOSIS. — Pileo fuligineo-fusco, rimosello-granuloso e verruculis punctiformibus, centro leviore, margine extremo striato, demum infundibuliformi, c. 60 mm. lato; granulis e sphaerocystis accumulatis, saepe ovoideis, paucis in hyphas ellipsoideas vel cylindraceas elongatis, omnibus crassotunicatis, constantibus; pigmento intracellulari dissolutoque et granuloso-globuloso ochraceo-brunneo manifesto; membranis 0.6-2 µm crassis, refringentibus. Lamellis albis, brunnescentibus fractu, sublinearibus, haud ventricosis, angustis, lamellulis perpaucis intermixtis, tenuibus, adnexis, confertissimis; sporis in cumulo haud visis, probabiliter albis vel albo-cremeis, sub microscopio 6.8-9.5 × 6-8.8 µm, distincte asymmetricis, subglobosis, plerumque 7-7.5 × 6-6.5 µm, ornamentatione 0.2-0.5 µm alta, cristulato-reticulata (typi I); basidiis c. 24 × 7 µm, tetrasporis; sterigmatibus 5-5.5 µm longis; cystidiis 32-53 × 4-10.5 µm, versiformibus, clavatis, fusoideis, etc., apice acutis vel rotundato-obtusis, intus granulosis vel corpusculis vermiformibus impletis; tramate sphaerocystis numerosis praedito. Stipite cremeo-albido, tactu brunneolo-albido, furfuraceo-granuloso, spongioso, solido, aequali, c. 55 × 14 mm.; granulis e corpusculis eis pilei similibus, sed magis elongatis, plerumque catenulatis efformatis; membris individualibus catenulae 5.5-13 µm crassis, membrana c. 0.7 µm crassa, intus subgranulosis. Carne alba , in pileo fragili, in stipite spongioso; odore terreo; sapore haud notato; sulphovanillinae actione haud mutata sed granulis externalibus nonnullis brunnescentibus. In terra humosa , verne. Nengbe, Liberia. G. W. Harley, 50.

DESCRIPTION

Pileus

Rather fleshy, 60 mm diam., plane, then widely depressed in the center; margin most likely smooth, surface layer not separable, dull, finely tomentose under a hand lens, brownish gray, profusely fissured-areolate in appressed squamulae.

Lamellae

Shortly adnexed, not brittle, probably equal, dense, narrow and 3 mm high, narrowing toward the extremities, whitish, browning when touched.

Stipe

Firm, c. 55 × 14 mm, subcylindrical, dull, smooth, creamcolored, spongiose inside.

Context

White, browning when cut in the stipe.

Smell

Insignificant, of soil.

Taste

Mild.

Spore print

Not obtained, most likely cream, certainly pale.

Spores

Subglobose, 6.4-6.79-7.3 × 5.8-6.35-6.8 µm, (Q = 1.02-1.07- 1.13; n = 20), densely ornamented with obtuse, isolated warts, <0.5 µm high, from minutely verrucose to hemisphaerical or droplet-like, sometimes laterally prolonged or locally confluent but not forming crests and without any form of reticulation, distinctly amyloid; suprahilar spot not amyloid, verrucose and densely covered with minute, hardly amyloid warts.

Basidia

40- 48 × 9-13 µm, four-spored; sterigmata 6-8 × 1.5-2.5 µm.

Cystidia

Very numerous on the gill edge, much less so on the gill sides, 40-70 × 8-11 µm, fusiformous to clavate, obtuse-rounded or mucronate-appendiculate, thin- to slightly thick-walled, filled with abundant cristalline contents that hardly react to SV.

Marginal cells

Not differentiated.

Pileipellis

Two-layered, orthochromatic in Cresyl blue; subpellis poorly gelified but not very dense, composed of 5-10 µm wide, rather densely septate, intertwined hyphae; suprapellis discontinuous but dense, forming an fragmented trichoderm of densely septate and strongly ramified, thin- to slightly thick-walled hyphal extremities that are composed of cells of variable dimensions, often cylindrical or ellipsoid, but also more irregular and variable in outline, mostly filled with a brownish, granular-guttate pigment; terminal cells mostly attenuated toward the apex, obtuse, sometimes subcapitate; pileocystidia absent. Stipitipellis less differentiated and showing very long, cylindrical, thin-walled caulocystidia running below the stipe surface in the lower stipe portion, c. 3-6 µm wide and filled with typical, granular to crystalline, refringent contents.

Clamp connections

Absent from all tissues.

NOTES

Our description of field characters is based on Harley’s field notes, which explains why it deviates from Singer’s original description on several points. However, one of the most important differences between Singer’s description and our own observations consists in our inability to find the thick-walled cells in the pileipellis, with cell walls mentioned by Singer as “up to 2 µm” thick! This feature was his main argument for suggesting affinities with the American R. crassotunicata Singer. In addition, several of Singer’s measurements are inaccurate being distinctly to low with only 24 × 7 µm for basidia and 32-53 × 4-10.5 µm for hymenial gloeocystidia. Singer’s spore measurements are, on the contrary, far too high (even when knowing that Singer often included spore ornamentation in his measurements, which in this case would not have had a profound impact). Also Singer’s description of spore ornamentation is difficult to conceal with what we observed on the type. Like Singer, we were unable to find pileocystidia, but caulocystidia are definitely present on the lower stipe. We also confirm Singer’s mention of yellowish brown globules inside the hyphal extremities of the pileus, in a similar way as these exist in, e.g. the Central African R. meleagris Buyck.

Both the macroscopic and microscopic features (spore ornamentation and elements of the pileipellis) strongly suggest that R. liberiensis belongs in Russula subg. Malodora sect. Edules . If so, it is most likely that frequent gill forkings are also present in R. liberiensis , contrary to Singer’s description, mentioning only the presence of rare lamellulae. The Malagasy R. antsikana Buyck & Randrianjohany , sp. nov. differs from the type of R. liberiensis in the more reticulate-crested spore ornamentation and in the undeniable presence of pileocystidia, both at the pileus surface and in the underlying subpellis. Singer’s description also suggests that R. liberiensis is a much more fragile species, considering his mention of a striate pileus margin and fragile context, compared to the quite robust and fleshy basidiomata of R. antsikana Buyck & Randrianjohany , sp. nov.

Russula liberiensis “ sensu lato ” has previously been reported by us from Tanzania (in Härkönen et al 1993) and the Democratic Republic of the Congo ( Buyck 1993), while we (BB) may have collected it many years ago also in Burundi and Zambia based on the near identical field habit of our collections. Whether or not these morphologically similar specimens are conspecific remains to be verified by more collections and, in particular, by sequence data.

Figures

FIG. 20. — Russula liberiensis Sing. (holotype). Hyphal extremities of the pileipellis; note the strong branching and often subcapitate apices of the terminal cells. Note in the lower right corner a detail of zebroid incrustations that are clearly visible on most hyphal endings (and beneath). Drawings:B. Buyck. Scale bar:10 µm.

FIG. 21. — Russula liberiensis Sing. (holotype), microscopic elements of the hymenium. A, spores in Melzer’s reagent; B, basidia; C, basidiola; D, pleurocystidia (left) and cheilocystidia (right) with contents schematically indicated in all but one. Drawings: B. Buyck. Scale bar: A, 5 µm; B-D, 10 µm.