China. Guizhou Prov., Leishan County, Leigong Mountain, ca. 1600 m elev., 26°22'N, 108°12'E, on decaying stump of fagalean tree, 19 July 2014, X.L. He (SAAS 1080, holotype; ZT 13612, isotype).

KU312115 (ITS), KU534217 (nLSU), KU534470 (RPB2).

flabellatum (Lat.), referring to the fan-like shape of the basidiomes.

Entoloma flabellatum is separated from the sympatric E. pleurotoides by the more heterodiametric basidiospores.

Pileus 5–15 mm, conchate, broadly convex, becoming applanate with age, entirely matted-tomentose to matted-appressed fibrillose, membranous, whitish at first, becoming orange-white, yellowish-white to pale pinkish with age, weakly hygrophanous, non-striate to minutely sulcate-striate towards margin, dry. Lamellae 6–15, with 2–3 tiers of lamellulae, adnexed, distant, narrow, ventricose, up to 1.5 mm wide, white at first, becoming pinkish with age, entire edges concolorous. Stipe 1–2.5 × 0.5–1 mm, lateral, strongly reduced, pale grey-brown, covered with minute pale grey fibrils, base with white mycelium and prominent white rhizoids. Context thin, unchanging. Odour and taste not distinctive.

Basidiospores 8–10.5 (11) × 6–7 (7.5) µm (x = 8.9 ± 0.3 × 6.4 ± 0.3 µm), Q = 1.26–1.52, Q = 1.38 ± 0.04, 5–7-angled, heterodiametric in profile view. Basidia 28–38 × 7–8 µm, slender clavate, 4-spored, clampless. Lamellar edge fertile. Cheilocystidia, pleurocystidia and caulocystidia absent. Pileipellis a cutis composed of cylindrical hyphae, terminal cells (25–) 30–80 × 6–10 µm, repent or slightly uplifted, subclavate, non-gelatinised walls thin, smooth or minutely encrusted with yellowish pigment, subpellis composed of short-celled cylindrical hyphae, 6–20 µm diam. Oleiferous hyphae absent. Clamp connections present in pileipellis.

On decaying stump of fagalean tree, in bamboo forest.

China. Guizhou Prov., Leishan County, Leigong Mountain, ca. 1600 m elev., 26°22'N, 108°12'E, on decaying stump of fagalean tree, 18 July 2014, X.L. He (SAAS 1501, ZT 13605).

Entoloma flabellatum is distinguished by the small and pleurotoid basidiomes, prominent white rhizoids attached to the rudimentary lateral stipe and (5–) 6-angled basidiospores measuring 7.5–8.5 × 5.5–6.5 µm. The basidiomes are white at first but gradually change to yellowish or orange with age.

Numerous species of Claudopus recorded from SE-Asia and Australasia are characterised by white basidiomes, cf. Horak (1980), Manimohan et al. (2002), Noordeloos (2004), Largent et al. (2011) and Noordeloos and Gates (2012). The Chinese E. flabellatum closely resembles the following three taxa recently described from Australia viz. E. pitereka which differs by larger basidiospores (8–12 × 6–8 µm, Noordeloos and Gates 2012), spermatic odour and nutty taste. In addition, the ecology of E. flabellatum and E. pitereka differs distinctly: E. pitereka is reported to occur on rotten wood-bark in wet Eucalyptus forest, while E. flabellatum is found on rotten wood-bark in subtropical bamboo forest of SW-China. C. minutoincanus is also similar to the Chinese E. flabellatum, but is distinguished by more isodiameteric basidiospores (7.4–11.4 × 6.3–9.6 μm, Q = 1.08–1.44, Largent et al. 2011). In addition, the RPB2 sequence of E. flabellatum is 97% identical to that of C. minutoincanus, indicating that they are closely related, but separate species. Macroscopically and microscopically C. viscosus is difficult to separate from E. flabellatum. However, apart from different size of the basidiospores, the RPB2 sequences of the two species have no significant molecular similarity and thus indicate to represent different and not closely related species (Fig. 9).