Dermoloma indicum K.N.A. Raj & Manim., 2014

Anil Raj, K. N., Deepna Latha, K. P., Paramban, Raihana & Manimohan, Patinjareveettil, 2014, Two new species of Dermoloma from India, Phytotaxa 177 (4), pp. 239-243 : 239-241

Dermoloma indicum K.N.A. Raj & Manim. , sp. nov., Fig. 1. A–H

MycoBank MB 808549

Diagnosis:—Characterized by a dark brown pileus with a wrinkled and finely appressed-squamulose surface, white spore print, amyloid basidiospores, hymeniderm-type pileipellis, cutis-type stipitipellis, absence of cystidia, a distinct dark brown band in the pileus trama, and presence of clamp connections. Differing from Dermoloma cystidiatum Manim. & Arnolds (1998: 149) in having smaller basidiomata, a fertile lamella edge, and much larger and differently shaped basidiospores.

Type:— INDIA. Kerala State: Thrissur District, Peechi Forest , 7 December 2010, Anil Raj K. N. (K(M) 190589, holotype) .

Basidiomata tricholomatoid. Pileus 6–21 mm diam., almost hemispherical when young, becoming convex with age; surface dark brown (6F7) at the center, gradually fading to brownish orange (6C5) towards margin, not hygrophanous, not pellucid-striate, finely wrinkled at and around the center, finely appressed-squamulose all over, denser towards the center; margin incurved, initially entire, becoming somewhat wavy. Lamellae adnate or adnate with a decurrent tooth, transvenose as well as intervenose, occasionally furcate, subdistant, orange-white (5A2), up to 4 mm broad; edge entire, concolorous with the sides; single tier of lamellulae. Stipe 12–18 × 2–4 mm, central, terete, slightly tapering towards the base, fistulose; surface orange-gray (5B2) when young, becoming brownish gray (5E2), appressed-fibrillose all over; base with whitish mycelial cords. Odor and taste not distinctive. Spore print white.

Basidiospores 7–14 × 3.5–6 (10.57±1.90 × 4.67±0.73) µm, Q = 1.52–3.14, Qm = 2.29, oblong-ellipsoid, subcylindrical or subamygdaliform, thin-walled, hyaline, smooth, with several tiny oil globules, amyloid. Basidia 26– 31 × 5–8 µm, narrowly clavate, hyaline or pale yellow, 4-spored, rarely 2-spored; sterigmata ca. 3 µm long but in some rare two-spored basidia up to 11 µm. Lamella edge fertile. Cheilocystidia and pleurocytidia absent. Lamella trama almost regular; hyphae 2–9 µm wide, thin-walled, with very pale brownish yellow plasmatic contents, inamyloid. Pileus trama interwoven made up of pale brown, thin-walled hyphae 3–11 µm wide, the central part of pileus trama often showing a distinct dark brown band owing to concentration of both brown wall pigment and brown contents in the hyphae of that region. Pileipellis a unistratous to pluristratous hymeniderm made up of erect, branched hyphae with clavate, broadly clavate, pyriform, sphaeropedunculate or suglobose terminal cells, 14–44 × 10–15 µm, with a slightly thickened, brownish wall. Stipitipellis a cutis composed of thin-walled hyphae, 2.5–8.5 µm wide, with a pale brownish yellow wall pigment. Clamp connections observed on all hyphae.

Habitat/Distribution:—In small groups on forest floor, among litter, Kerala State, India.

Etymology:—Specific epithet “indicum” refers to India, the country where this species was first observed.

Notes:— The finely appressed-squamulose pileus and the dark brown band in the middle of the pileus trama together make this species unique among Dermoloma species. Owing to its amyloid basidiospores, Dermoloma indicum belongs to the section Atrobrunnea Singer (1986: 424) ex Contu (1992: 80). Dermoloma cystidiatum Manimohan & Arnolds (1998: 149), the only other species known from the region, has many macroscopic similarities; it however, differs in having a sterile lamella edge with crowded cheilocystidia, much smaller (3.5–6 × 3–4 µm), broadly ellipsoid basidiospores and a gray discoloration of the lamellae on bruising. Dermoloma scotodes (Berkeley & Broome 1871: 522) Pegler (1986: 182) from Sri Lanka has smaller (5.2–6.5 × 3.2–3.7 µm) basidiospores and a white flocculose stipe (Pegler 1986). Dermoloma atrobrunneum (Dennis 1951: 476) Singer (1955: 375) ex Bon (1986: 51), a Caribbean species, is very close in morphology but has smaller, subglobose to ovoid basidiospores (Pegler 1983). Dermoloma hemisphaericum (Stevenson 1964: 14) E. Horak (1971: 429) from New Zealand has a grayish sepia pileus and oblong-ovoid, much smaller (5–6 × 3.5–4 µm) basidiospores (Horak 1971). Dermoloma murinum (G. M. Taylor & Stevenson 1964: 17) E. Horak (1971: 438), another New Zealand species, has moderately crowded, sinuate lamellae and much smaller (5.5–7 × 3.5–4 µm) inamyloid basidiospores (Horak 1971). Dermoloma josserandii Dennis & P. D. Orton (1960: 226), a European species, has smaller (4.5–7 × 3.6–4.8 µm) basidiospores (Arnolds 1995). Dermoloma pseudocuneifolium Herink (1958: 62) ex Bon (1986: 52), another European species, has much darker brownish or grayish lamellae and smaller basidiospores (Arnolds 1995).

Figures

FIGURE 1. A–H: Dermoloma indicum (K(M)190589). A. Basidiomata; B. Basidiospores; C. Lamella trama; D. Basidium; E. Pileipellis; F. Stipitipellis; G. Elements of the pileipellis; H. Pileus trama with dark brown band. Scale bars: A=10 mm; B–H=10 µm.