Dermoloma keralense 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 : 241-243

Dermoloma keralense K.N.A. Raj & Manim. , sp. nov., Fig. 2. A–E

MycoBank MB 808550

Diagnosis:—Characterized by a dark brown pileus with a wrinkled and waxy surface, grayish yellow lamellae, a white spore print, inamyloid basidiospores, pileipellis and stipitipellis with bluish green encrusting pigment, and hyphae with clamp connections. Differing from Dermoloma cuneifolium (Fries 1818: 99) Singer (1955: 375) ex Bon (1986: 51) , in having smaller basidiospores, grayish yellow lamellae, and a pileipellis and stipitipellis with a bluish green encrusting pigment dissolving in KOH.

Type:— INDIA. Kerala State: Kollam District, Thenmala Shenduruni Forest Division , 10 November 2010, Anil Raj K. N. (K(M) 190590, holotype) .

Basidiomata collybioid. Pileus 12–24 mm diam., convex to broadly convex with a slight umbo; surface dark brown (5F3) at the center, gradually fading to brownish orange (5E5) or light brown (5D5) towards margin, weakly hygrophanous and becoming paler, finely pellucid-striate towards margin, slightly wrinkled at and around the center, smooth and somewhat waxy; margin slightly incurved, crenate. Lamellae emarginate often with a small decurrent tooth, transvenose as well as intervenose, occasionally furcate, moderately close, grayish yellow (3B5, 4B5), up to 5 mm broad; edge entire, concolorous with the sides; with 3 tiers of lamellulae. Stipe 17–32 × 2–4 mm, central, terete, equal, hollow; surface grayish yellow (4B5) towards apex, orange-gray (5E5) towards base, appressed-fibrillose all over; base slightly enlarged, with white mycelial cords. Odor and taste not distinctive. Spore print white.

Basidiospores 3–4 × 2–3 (3.55±0.42 × 2.57±0.33) µm, Q = 1.16–1.6, Qm = 1.38, ellipsoid, thin- to slightly thickwalled, hyaline, smooth, inamyloid. Basidia 13–20 × 3.5–5 µm, clavate, with a few oil globules, yellowish brown, 4-spored; sterigmata up to 3 µm long. Lamella edge fertile. Cheilocystidia and pleurocystidia absent. Lamella trama almost regular; hyphae 3.5–14 µm wide, yellowish brown, thin-walled, inamyloid. Pileus trama almost regular; hyphae 3–12 µm wide, thin-walled, yellowish brown, faintly dextrinoid. Pileipellis a hymeniderm with clavate, subglobose, utriform or ellipsoid terminal cells, 19–52 × 12.5–22 µm, slightly thick-walled, with a bluish green encrusting pigment slightly dissolving in KOH. Stipitipellis a cutis, composed of hyphae 3–21 µm wide, with a greenish, granular, encrusting pigment. Clamp connections seen on all hyphae.

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

Etymology:—Specific epithet “keralense” refers to Kerala State, India, the region where this species was first observed.

Notes:—Because of the inamyloid nature of the basidiospores, Dermoloma keralense fits in the section Dermoloma J.E. Lange (1933: 12) ex Herink (1958: 62) . The yellowish lamellae contrasting with the dark brown pileus surface is a very distinctive field character of this species. Microscopically, the bluish green/green encrusting pigment that dissolves in KOH is also very distinctive. These two characters together make this species unique among the documented species of Dermoloma . Dermoloma cuneifolium , a European species belonging to the section Dermoloma , shares a few characters such as somewhat similar sized basidiomata, hollow stipe with similar surface features, inamyloid and ellipsoid basidiospores and a fertile lamella edge (Wilhelm 1992). However, D. cuneifolium has differently shaped basidiomata, larger basidiospores and caulocystidia. Dermoloma coryleti Singer & Clémençon (1971: 120) , D. intermedium Bon (1979: 42) and D. emiliae-dlouhyi Svrček (1966: 147) are some other European species with inamyloid basidiospores (Arnolds 1995), but all those species have much larger basidiospores.

Figures

FIGURE 2. A–E. Dermoloma keralense (K(M)190590). A. Basidiomata; B. Basidiospores; C. Basidium; D. Pileipellis; E. Stipitipellis. Scale bars: A=10 mm; B–E=10 µm.