Entoloma brunneoumbonatum K. N. A. Raj & Manim., 2016

Anil Raj, K. N. & Manimohan, Patinjareveettil, 2016, Three new species of Entoloma subgenus Nolanea from India based on morphology and molecular phylogeny, Phytotaxa 286 (4), pp. 232-244 : 233-235

Entoloma brunneoumbonatum K. N. A. Raj & Manim. , sp. nov. Figs. 1A–F

MycoBank MB 818066

Etymology:—The specific epithet refers to the brownish, umbonate pileus of this species.

Diagnosis:—This species is characterized by small to medium-sized, slenderly tricholomatoid basidiocarps; a yellowish brown pileus with a prominent umbo; sinuate or emarginate lamellae; quadrate or pentagonal basidiospores 9–13 × 8–11μm; cylindrical or clavate cheilocystidia; a disrupted cutis-type pileipellis; faint brown encrustations on hyphae of lamellar trama, pileipellis and stipitipellis; and a distinctive ITS sequence (KX774266).

Holotype:— INDIA. Kerala State: Malappuram District, Calicut University Campus , 22 October 2011, K. N. Anil Raj, AR904 ( CAL 1317 ).

Description:— Basidiocarps small to medium-sized, slenderly tricholomatoid. Pileus 8–38 mm diam., somewhat conical with a prominent obtuse umbo when very young, becoming somewhat campanulate or conico-convex with a mammillate or broad umbo and finally plano-convex or upturned with a slight depression around the umbo; surface dark brown (5F7, 5F8/OAC733) on the umbo and on the striations, yellowish brown (5D4, 5D5/OAC728) elsewhere, rather hygrophanous and becoming slightly paler, finely pellucid-striate, glabrous to the naked eye, finely appressed fibrillose all over under a lens; margin initially incurved, becoming decurved or reflexed with age, crenate or somewhat wavy, slightly fissile with age. Lamellae sinuate or emarginate or rarely emarginate with a small decurrent tooth, subclose, pale yellow (4A2/OAC900) or yellowish gray (4B2/OAC893) when very young, becoming orange white (5A2, 6A2/OAC759) or pale orange (6A3/OAC695) with age, up to 6 mm wide, with lamellulae in 2–3 tiers; edge entire to the naked eye, finely torn or crenate under a lens, concolorous with the sides. Stipe 22–104 × 2–6 mm, central, terete, equal or slightly tapering towards the apex, cartilaginous, hollow; surface grayish yellow (4B3/OAC829) when young, becoming grayish brown (5C3, 5C4/OAC745) or brownish gray (5D2, 5D3/OAC739), fibrillose-striate all over; base with fine, white, mycelial cords. Odor and taste not distinctive.

Basidiospores 9–13 × 8–11 (11.1±0.96 × 9.46±0.81) μm, Q = 1–1.3, Qm = 1.17, quadrate or pentagonal, subisodiametric to heterodiametric, hyaline, slightly thick-walled. Basidia 23–49 × 8–15 μm, clavate, hyaline, thin-walled, 4-spored; sterigmata up to 4 μm long. Lamella-edge sterile or occasionally heterogeneous. Cheilocystidia 23–54 × 6–15 μm, narrowly clavate, cylindrical or cylindrical with a median constriction, hyaline, thin-walled. Pleurocystidia none. Lamellar trama subregular, made up of both narrow and slightly inflated hyphae; hyphae 6–24 μm wide, with a pale brownish yellow intraparietal pigment and occasionally with faint brown encrustations, thin- to slightly thick-walled. Subhymenium inconspicuous. Pileitrama subregular, with both narrow and inflated hyphae as well as a few oleiferous hyphae; hyphae 6–33 μm wide, pale yellow, thin-walled. Pileipellis a cutis rarely disrupted by isolated erect hyphae; hyphae 6–17.5 μm wide, with a pale brownish yellow intraparietal pigment and occasionally with faint brown encrustations, thin- to slightly thick-walled. Stipitipellis a cutis; hyphae 3–11 μm wide, with a pale yellow or pale brownish yellow intraparietal pigment and faint brown encrustations, thin-walled. Caulocystidia absent. Clamp-connections observed on all hyphae.

Habitat:—scattered or in small groups, on soil, among leaf litter, under broadleaf trees.

Geographical distribution range:—known only from the type locality in Kerala State, India.

Additional specimens examined:— INDIA. Kerala State: Malappuram District, Calicut University Campus, 11 November 2009, K. N. Anil Raj, AR100 (CAL 1318).

Comments:—Characters such as the slenderly tricholomatoid habit, the conico-campanulate or conico-convex pileus with pellucid striations and a prominent umbo, the fibrillose-striate stipe, the sterile lamella-edge with cheilocystidia, the cutis-type pileipellis and stipitipellis with encrusting pigment and the presence of clamp-connections on all hyphae are indicative of the subsection Cosmeoexonema of the section Papillata belonging to the subgenus Nolanea ( Noordeloos 1992, 2004). Entoloma mammiferum ( Romagnesi 1956: 156) Noordel. & Co-David in Co-David et al. (2009: 170), an East African species ( Pegler 1977b; Co-David et al. 2009) subsequently also reported from India ( Natarajan & Raman 1980), resembles E. brunneoumbonatum in having a similar looking basidiocarp with a mammillate pileus, rather similar-shaped basidiospores and a cutis-type pileipellis with encrusting hyphae. However, E. mammiferum differs from E. brunneoumbonatum in having smaller basidiospores (7.5–11.5 × 6.3–9.9 μm), a fertile lamella-edge, a wide subhymenial layer (8–12 μm), and plasmatic pigments in the pileipellis hyphae and also in lacking clamp-connections. Entoloma maderaspatanum ( Pegler 1977a: 202) Horak (1980: 177) , a species known from southern India and Sri Lanka, resembles the present species in having a pileus with a rather similar color and shape, emarginate lamellae and a cutis-type pileipellis ( Pegler 1977a, 1986; Horak 1980), but it has smaller and differently shaped basidiospores and it lacks both cheilocystidia and clamp-connections.

In a BLASTn search using the ITS (654 bp) sequence of the present species, the closest hit was Entoloma sanvitalense (JX454801) with 86% sequence identity. Entoloma sanvitalense Noordeloos & Hausknecht (1998: 250) , a European species, resembles the present one in having a similar looking pileus with a prominent umbo and translucent-striate pileus of similar color, the presence of encrustations on both pileipellis and stipitipellis hyphae and presence of clamp- connections on all hyphae ( Noordeloos 2004). However, E. sanvitalense differs from the present species in having a smaller pileus with a tomentose-hairy pileus, a shorter and filiform stipe, a fertile lamella-edge, smaller and differently shaped basidiospores with slightly higher Q value, a cutis with a transition to a trichoderm-type pileipellis and a different geographical location.

Figures

FIGURE 1. A–F: Entoloma brunneoumbonatum (CAL 1317, holotype). A. Basidiomata; B. Basidiospores; C. Basidium; D. Hyphal septum showing clamp-connection; E. Pileipellis; F.Cheilocystidia. Scale bars: A = 10 mm; B–F = 10 μm. Photos by K. N. Anil Raj.