Rhodocybe indica K.N.A. Raj & Manim.

MycoBank MB 816841; Facesoffungi number: FoF02179

Etymology: The specific epithet refers to India, the country where this species was first observed.

Holotype: CAL 1323.

Basidiocarp small, mycenoid. Pileus 15 mm diam., broadly convex with a small umbo; surface brown (6E7/ OAC599) on and around the umbo, brownish-yellow (5C7/OAC790) towards the margin, weakly hygrophanous and becoming slightly paler, faintly pellucid-striate towards the margin, glabrous, somewhat tacky; margin slightly incurved and somewhat wavy. Lamellae narrowly adnate to adnate, subventricose, close, greyish-orange (6B3/OAC695), up to 3 mm wide, with lamellulae of 3–7 lengths; edge crenulate, concolourous with the sides. Stipe 30 x 2 mm, central, equal, slightly flexuous, cartilaginous, solid; surface brownish-yellow (5C7/OAC790), glabrous to the naked eye, finely pruinose all over under a lens; base with white mycelial cords. Odour and taste not distinctive. Basidiospores 6.5–8 x 5.5–7 (7.27 ± 0.49 x 6.1 ± 0.38) um, (Q = 1–1.3, Qm = 1.19), subglobose or lacrymoid, undulate-pustulate, with or without a suprahilar depression in profile view, 6 angled in polar view, hyaline, thin-walled. Basidia 18–33 x 7–8 um, narrowly clavate to clavate, pale yellow, thin-walled, 4-spored; sterigmata up to 5 um long. Lamella-edge heterogeneous. Cheilocystidia and pleurocystidia present as pseudocystidia. Pseudocystidia 24–40 x 4–9 um, scattered, fusiform, lanceolate or ventricose-rostrate, with glittering, yellow, granular contents, thin-walled. Lamellar trama subregular; hyphae 4–7 um wide, hyaline or pale yellow, thin-walled. Subhymenium inconspicuous. Pileus trama subregular; hyphae 5–14 um wide, pale yellow, thin-walled. Pileipellis an undifferentiated cutis, made up of closely septate and compactly arranged hyphae with widely scattered pileocystidia; hyphae 5–13 um wide, slightly gelatinised, with a pale brownish-yellow wall pigment and fine hyaline encrustations, thin- to slightly thick-walled. Pileocystidia 21–42 x 3–11 um, scattered, versiform: nettle hairshaped, narrowly fusiform or flexuous, hyaline or pale yellow, thin-walled. Stipitipellis a cutis, rarely disrupted by flaring out hyphae; hyphae 3–9 um wide, with a pale brownish-yellow wall pigment, thin-walled. Caulocystidia absent. Clamp connections not observed on any hyphae.

Habitat: on a decaying twig, solitary.

Specimens examined: INDIA, Kerala, Kollam District, Thenmala, Thenmala Forest, 17 August 2013, K. P. Deepna Latha DKP130 (CAL 1323, holotype).

Notes: Rhodocybe indica is well-characterized by its small basidiocarps with a brownish-yellow, umbonate pileus; subglobose or lacrymoid basidiospores; smaller, fusiform, lanceolate or ventricose-rostrate pseudocystidia; a pileipellis with pileocystidia and a stipitipellis lacking encrusted hyphae. Characters such as the centrally stipitate basidiocarps and the presence of pseudocystidia indicate the section Rhodocybe (Baroni 1981). Rhodocybe pruinosistipitata T.J. Baroni et al., a species reported from Pakaraima Mountains of Guyana (Henkel et al. 2010), is somewhat comparable to the present species because of a similar looking pileus, a pruinose stipe, adnate lamellae, somewhat similar sized basidiospores, abundant pseudocystidia and a similar habitat. However, R. pruinosistipitata has a longer stipe, pip-shaped basidiospores, larger, (GenBank AF261283; Identities = 853/884 (96 %)). Rhodocybe fallax (Que ´l.) Singer), belonging to the section Decurrentes (Baroni 1981), and differs from the present species in almost all macro- and micromorphological characters. In the resulting phylogenetic tree after the ML analysis, Rhodocybe indica, R. collybioides and R. caelata formed a distinct clade with significant support (73 % BS). Within this clade, R. indica is related to R. collybioides with weak support (67 % BS).

RPB2-based phylogram generated from maximum likelihood analysis (RAxML) depicting the placement of Rhodocybe indica, R. luteobrunnea and R. griseoaurantia within the genus Rhodocybe. Values at nodes indicate bootstrap support. BS values C50 % are indicated above or below the nodes, new species are in blue bold. The tree is rooted with Tricholoma flavovirens (KC816997) and Catathelasma imperiale (KC816994)

RPB2-based phylogram generated from maximum likelihood analysis (RAxML) depicting the placement of Rhodocybe indica, R. luteobrunnea and R. griseoaurantia within the genus Rhodocybe. Values at nodes indicate bootstrap support. BS values C50 % are indicated above or below the nodes, new species are in blue bold. The tree is rooted with Tricholoma flavovirens (KC816997) and Catathelasma imperiale (KC816994).

Rhodocybe indica (CAL 1323, holotype). a Basidiospores. b Basidium. c Pseudocystidia. d Stipitipellis. e Pileipellis with pileocystidia. f Basidiocarp in the field. Scale bars a–e = 10 lmf= 10 mm (a–e Photo by K.P. Deepna Latha, f Photos by K.N. Anil Raj)

Rhodocybe indica (CAL 1323, holotype). a Basidiospores. b Basidium. c Pseudocystidia. d Stipitipellis. e Pileipellis with pileocystidia. f Basidiocarp in the field. Scale bars a–e = 10 um f= 10 mm (a–e Photo by K.P. Deepna Latha, f Photos by K.N. Anil Raj)