Entoloma silvanum K. N. A. Raj & Manim., 2017

Anil Raj, K. N. & Manimohan, Patinjareveettil, 2017, Four new species of Entoloma subgenus Pouzarella from India, Phytotaxa 307 (2), pp. 101-112 : 107-108

Entoloma silvanum K. N. A. Raj & Manim. , sp. nov. Figs. 3A–F

MycoBank MB 820067

Etymology:—The specific epithet refers to the sylvan (wooded) type locality of this species.

Diagnosis:—Characterized by a greyish brown to brown, conico-convex or conico-campanulate pileus, absence of both cheilo- and pleurocystidia, basidiospores measuring 10–15 × 6.5–9 μm, and distinctive ITS (KY643747) and nLSU (KY643724) sequences. Differing from Entoloma testaceostrigosum in having emarginate lamellae with decurrent teeth, a hollow and basally tapering stipe, and slightly smaller-sized basidiospores.

Holotype:— INDIA. Kerala State: Thrissur District, Peechi Forest : 7 December 2010, K. N. Anil Raj AR555 (K(M) 191739).

Description:— Basidiocarps small, mycenoid. Pileus 3–11 mm diam., convex when very young, becoming conico-convex or conico-campanulate with or without a very small central depression with age; surface brown (6 E5, 6 E6/OAC720) at the center, grayish brown (5 E3, 5 F3/OAC640) elsewhere, not hygrophanous, with or without faint striations, with short, recurved hairs all over; margin slightly incurved when young, becoming deflexed with age, initially crenate, becoming finely wavy at maturity. Lamellae emarginate or emarginate with a small decurrent tooth, close, brownish gray (5D2/OAC548) when young, becoming grayish brown (6 E3,6 F3/OAC640) at maturity, up to 4 mm wide, with lamellulae in 2–3 tiers; edge initially entire, becoming somewhat wavy at maturity, concolorous with the sides. Stipe 9–28 × 1–2 mm, central, terete, or slightly compressed, equal or slightly tapering towards the base, cartilaginous, hollow; surface brownish gray (5E2/OAC724) or grayish brown (5E3/OAC640) or gray (5F1, 5F2/ OAC641), finely tomentose all over; base with a strigose basal mycelium. Odor and taste not distinctive.

Basidiospores 10–15 × 6.5–9 (12.1±0.77 × 7.4±0.74) μm, Q = 1.25–2.14, Qm = 1.62, nodulose-multiangled, heterodiametric-ovate, with 6–9 concave or flat facets, pale brownish yellow, thick-walled. Basidia 29–43 × 11–15 μm, clavate, with a pale brownish yellow wall pigment, occasionally with dense, dark brown contents, 4-spored; sterigmata up to 5.5 μm long. Crassobasidia frequent in the hymenium. Lamella-edge fertile. Cheilocystidia and pleurocystidia absent. Lamellar trama subregular; hyphae 3–12 μm wide, with a yellowish brown wall pigment and dark brown external spiral encrustations, thin- to slightly thick-walled. Subhymenium inconspicuous. Pileus trama subregular; hyphae 4–14 μm wide, with a yellowish brown wall pigment and dark brown external encrustations, slightly thick-walled. Pileipellis a cutis with a transition to a trichoderm; hyphae 5–13 μm wide, with a pale brownish yellow wall pigment and dark brown external encrustations, slightly thick-walled; terminal cells 37–110 × 8–25 μm, cylindrical or gradually tapering with an obtuse apex. Stipitipellis a loose trichoderm of entangled, hair-like, multiseptate hyphae; hyphae 4–10 μm wide, cylindrical or tapering with an obtuse apex, with a yellowish brown wall pigment and dark brown external encrustations, thick-walled. Caulocystidia absent. Clamp connections not observed on any hyphae.

Habitat: — scattered or in small groups, on the forest floor, among decaying leaf litter and humus, under broadleaf trees.

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

Comments:—The grayish brown, non-hygrophanous pileus with a recurved-hairy surface, the brownish gray stipe with a tomentose surface, the nodulose-angular basidiospores and the presence of brown external encrustations on all hyphae of E. silvanum are indicative of the section Dysthales . Entoloma testaceostrigosum Manim. & Noordel. in Manimohan et al. (2006: 50), a species previously described from Kerala, resembles E. silvanum in having a hairy and convex pileus, somewhat similar-sized (12.5–17 × 7–10 μm) basidiospores with 7–9 angles, a hymenium lacking both cheilo- and pleurocystidia, a trichoderm-type pileipellis and a loose trichoderm-type stipitipellis composed of entangled, thick-walled hyphae with a yellowish brown externally encrusting pigment. However, that species has deep orange to light brownish basidiocarps, narrow (1 mm or less), sinuate and subcrowded lamellae, a solid and apically tapering stipe and slightly larger basidiospores (12.5–17 × 7–10 μm). Entoloma lomapadum Manim., Joseph & Leelav. in Manimohan et al. (1995: 1084), another species previously described from Kerala, resembles E. silvanum in having a dark brown or brownish beige, conico-convex pileus, a stipe base with strigose mycelium and heterodiametric-elliptic basidiospores with 8–9 facets in profile and of somewhat similar size (11–13 × 6–9 μm) ( Manimohan et al. 1995). However, that species differs from E. silvanum in having a larger pileus (25 mm), adnate lamellae, a longer stipe (40 mm) with a pruinose apex, a distinct, unpleasant odor, the presence of clavate, thin-walled cheilo- and caulocystidia and a well developed, cellular subhymenium. Entoloma lasium ( Berkeley & Broome 1871: 539) Noordel. & Co-David in Co-David et al. (2009: 170), from Sri Lanka ( Horak 1980; Pegler 1986) somewhat resembles E. silvanum in having basidiocarps of similar color and size, short hispid hairs on the pileus, basidiospores of almost similar size and shape and lamella-edge devoid of cheilocystidia. However, that species differs in having a depressed pileus, crowded and sinuate-adnate lamellae, a well developed subhymenium and presence of thin- to thick-walled caulocystidia.

A megablast search of the GenBank nucleotide database using the ITS and the nLSU sequences derived from E. silvanum showed that these sequences were distinct. The BLASTn results using the ITS (742 bp) sequence showed no close hit with an e-value of zero. Entoloma furfuraceum (GenBank JQ993094) with 94% sequence identity was the closest hit with the nLSU (869 bp) sequence. Entoloma furfuraceum T.H. Li & Xiao Lan He in He et al. (2013: 234) somewhat resembles E. silvanum in the size and shape of the pileus. However, it differs from the present species in having a differently colored pileus, a longer stipe, smaller-sized basidiospores (9–11 (–13) × 6.5–8 μm) and a sterile lamellae edge with cheilocystidia ( He et al. 2013). The pairwise alignment of the ITS sequence of Entoloma silvanum with those of the other three species described showed no similarity with an e-value of zero. However, the nLSU sequence of E. silvanum showed 88% similarity with that of E. peechiense and 91% with that of E. tropicum . No similarity with an e-value of zero was observed in a pairwise comparison of the nLSU of E. silvanum with E. wayanadense .

Figures

FIGURE 3. A–F: Entoloma silvanum (K(M) 191739, holotype). A. Basidiomata. B. Basidiospores; C. Basidium; D. Lamellar trama; E. Pileipellis; F. Stipitipellis. Scale bars: A= 10 mm; B–D & F= 10 μm; E=100 μm. Photos by K. N. Anil Raj.