Russula, Rossi, Walter, Das, Kanad, Hembrom, Manoj Emanuel, Santamaria, Sergi, Parihar, Arvind, Ghosh, Aniket, Henkel, Terry W., Hofstetter, Valerie & Randrianjohany, Émile, 2020

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 : 101

100. Russula subsect. Castanopsidum Buyck & X. H. Wang, subsect. nov.

( Figs 22-25 )

Pileus dull, dry, hardly peeling, variously colored, rapidly rupturing and fissurate, becoming areolate, granular, context unchanging when cut, mild and without particular smell. Stipe slender and typically longer than pileus diameter, hollowing, often furfuraceus and with the same color as the pileus. Lamellae equal, adnate, pale colored. Spore print pale (off-white to cream). Basidiospores never reticulate; ornamentation composed of spines which are completely isolated or sparsely interconnected; suprahilar spot distinct and amyloid. Hymenium composed of relatively wide and short basidia and dispersed gloeocystidia with poor contents and sometimes slightly thickened walls. Pileipellis orthochromatic in Cresyl blue, pseudoparenchymatic, composed of inflated, thin-walled, gradually narrowing cells, without gloeoplerous elements (neither pileocystidia near the surface, nor cystidioid hyphae in the context), but ending in dispersed, encrusted, cylindrical cells that usually surpass the general pileipellis surface.

TYPE SPECIES. — R. castanopsidis Hongo, Notulae Mycologicae 12: 42 (1973).

MYCOBANK. — MB 834837.

GENBANK. — R. castanopsidis : MN134522‒MN134533 (ITS); MN134540‒MN134541 (LSU);MN158651‒MN158652 (mitSSU); MN165069‒MN165070 (rpb1); MN165065‒MN165066 (rpb2); MN165061‒MN165062 (tef1); R. purpureogracilis : MN134534‒

Figures

FIG. 22. — Russula castanopsidis Hongo, the type species of subsect. Castanopsidum Buyck & X. H. Wang, subsect. nov.; microscopic features of the type col- lection. A, vertical section of the pileipellis; B, hyphal terminations of the pileipellis; C, basidia; D, basidiola; E, hymenial gloeocystidia on gill sides; F, hymenial gloeocystidia on gill edge; G, marginal cells, H, spores in Melzer’s reagent. Drawings: B. Buyck. Scale bars: A-H, 10 µm.

FIG. 23. — Part of the most likely tree obtained by ML analysis of a 168 specimens/5 locus dataset (-ln 57423.49377). For details on vouchers, see Buyck et al. (2018); only subgenus Russula is here depicted; other subgenera are as shown in Buyck et al. (2018).Branches significantly supported are in bold and bootstrap values indicated along the branches. Newly sequenced taxa are in blue font and the new section is indicated as a green rectangle.

FIG. 24. — Russula purpureogracilis Hampe & Looney, field habit (coll. X. H. Wang, no 4515 [HKAS104817, PC0125102], no. 4516 [HKAS104818, PC0125103]), Photos: B. Buyck.

FIG. 25. — Russula castanopsidis Hongo field habit (coll.B. Buyck & X.H. Wang,no.4524 [HKAS 104824,PC0125085]). Photos: B.Buyck.