Index Fungorum number: IF 817515
Pileus 7–15 mm, conchate, broadly convex, at first white, becoming orange-white, yellowish-white and finally pale pinkish in age, entirely matted-tomentose to matted-depressed fibrillose, opaque, dry, not hygrophanous, margin not transparent-striate. Lamellae with 2–4 tiers of lamellulae, adnexed, up to 2 mm wide, subventricose, subdistant, white at first, becoming pinkish in age, entire margin concolorous. Stipe 1–3 × 0.5–1 mm, lateral, strongly reduced, covered with minute, white fibrils, base with white mycelium. Rhizoids absent. Context white, thin, unchanging. Odour and taste not distinctive. Basidiospores 8–10 (10.5) × (6) 6.5–8 μm (x = 9.0 ± 0.3 × 7.3 ± 0.3 μm), Q = 1.2–1.4, Q = 1.28 ± 0.03, 5–6-angled, heterodiametric in profile view. Basidia 28–34 × 9–12 µm, subclavate, 4-spored (also often 2-spored). Lamellar edge fertile. Cheilocystidia, pleurocystidia and caulocystidia absent. Pileipellis a cutis composed of cylindrical hyphae, terminal cells (25–)35–50 × 4–7 µm, cylindrical (or slender subclavate, weakly gelatinised wall thin, smooth or minutely encrusted with pale yellow pigment. Oleiferous hyphae numerous in pileipellis. Clamp-connections present in all tissues.
Habitat: Amongst moss on stem base of living conifers and fallen branches of conifers (Pinus sp., Picea sp.), or on roadside in conifers forest or broadleaf forest.
Additional materials examined: CHINA. Sichuan Prov., Miyi County, Huangqiao Reservoirs, ca. 1500 m elev., 26°42'N, 101°41'E, on soil, 13 September 2015, X.L. He (SAAS 1415); on fallen branches of conifers, 13 September 2015, X.L. He (SAAS 1117); X.L. He (SAAS 1378); amongst moss on stem base of living conifers, 13 September 2015, X.L. He (SAAS 1470); on soil, 13 September 2015, X.L. He (SAAS 1014; ZT 13609; SAAS 1364; ZT 13615). Yunnan Prov., Jinghong County, Dadugang, ca. 1200 m elev., 22°30'N, 101°45'E, on soil, 27 August 2011, X.L. He and M. Zhang (GDGM 28817).
Notes: Entoloma conchatum is characterised by basidiomes gradually changing colour from white to pinkish, matted-fibrillose pileus, 5–6-angled basidiospores and presence of clamp connections. Macromorphologically (white fibrillose basidiomes), the following taxa resemble E. conchatum viz. E. crepidotoides W.Q. Deng & T.H. Li, recently described from tropical China, E. indocarneum Manim., Leelav. & Noordel. from India, E. exiguum Esteve-Rav. & M. de la Cruz, E. jahnii Wölfel & Winterh. and E. parasiticum from Europe, Claudopus minutoincanus Largent & Abell-Davis, E. pitereka Noordel. & G.M. Gates, C. rupestris Largent & Abell-Davis and C. viscosus Largent & Abell-Davis from Australia and, finally, C. pandanicola E. Horak from Papua New Guinea. However, E. jahnii, E. exiguum and E. parasiticum are readily distinguished by the much larger basidiospores (9.4–12 × 6.4–8.3 µm, 9.5–12.5 × 8–10.5 µm, 9.7–12.9 × 7.6–10.2 µm. Entoloma pitereka differs in the prominent basal rhizomorphs and larger basidiospores (8–12 × 6–8 µm); C. pandanicola is separated by the translucent striate pileus and smaller basidiospores (7–8 × 6.5–7.5 µm). C. minutoincanus is different from E. conchatum in the sticky pileus and absence of clamp connections; C. rupestris is separated by the 4–5-angled and smaller basidiospores (6.5–9.2 × 6–8 µm) and absence of clamp connections; C. viscosus is distinctive by the presence of rhizoids and absence of clamp connections. The only white Claudopus species recently described from tropical China, E. crepidotoides, is recognised by the smaller basidiospores (8–9 × 6–7 µm. E. indocarneum) is readily distinguished from E. conchatum by its smooth pileus, presence of mycelial rhizoids and narrower basidiospores (7.5–10 × 5–7 µm).
Fig. 1 Phylogenetic reconstruction of Claudopus based on ITS sequences. Maximum parsimony bootstrap values (BS > 50%) are indicated above or below the branches, new species are in bold.