Clitopilopsis albida S.P. Jian & Zhu L. Yang
Basidiomata clitocyboid, small. Pileus 10–30 mm wide, plano-convex to convex, often slightly depressed at center; surface dirty white (2A1) to pale cream (2A2), usually smooth or in pruinose; margin incurved to straight, often applanate or undulate in age; context thin, around 2 mm thick, grayish white (1A2). Lamellae decurrent, flesh-colored (5A4–5), somewhat crowded to slightly sparse, around 2 mm deep, edges entire and concolorous, very fragile, lamellulae mainly distributed on edges, nonattached to lamellae. Stipe 20–30 × 1–5 mm, central to eccentric, subcylindrical to applanate, subequal, hollow; surface flesh-colored (4B4) to ochraceous yellow (5B4–5), strongly gelatinized. Odor farinaceous or strongly farinaceous. Basidiospores (6–)7–9.5 × (5.5–)6–8.5(–9) μm, Lm × Wm = 7.94 (± 0.76) × 7.10 (± 0.82) μm, Q = 1.00–1.29 (Qavg = 1.12 ± 0.07) [44/2/2], nearly hyaline, usually with thickened walls (0.3–0.8 μm), globose to subglobose and sometimes broadly ellipsoid in profile view, slightly angled in polar or face view with obscure minute pustules or bumps. Basidia 22–30 × 9–10 μm, clavate, hyaline, 4-spored, rarely 2-spored; sterigmata up to 7 μm long. Lamellar trama more or less regular, composed of hyaline hyphae, 3–15 μm wide; subhymenium composed of 4–5 layers of inflated or ovoid hyphal segments, these 5–12 × 3–8 μmwide. Lamellae edges fertile. Pleurocystidia 35–47 × 8–16 μm, abundant, clavate or branched with 2–6 septa. Cheilocystidia 37–64 × 8–19 μm, abundant, sometimes branched, clavate, with 2–4 septa. Pileipellis an ixocutis composed of more or less radially and loosely arranged, strongly gelatinized, hyaline, smooth, cylindrical hyphae, these 3–10 μm wide; subcutis made up of compactly arranged, thin-walled, hyaline, smooth, cylindrical hyphae, 3–12 μm wide. Stipitipellis an ixocutis composed of compactly arranged, strongly gelatinized, thin-walled, hyaline hyphae, 3–10 μm wide, with some slowly upturned terminal hyphae. Caulocystidia absent. Clamp connections absent.
Ecology and distribution: Scattered or in groups on alpine meadow with Carex and Polygonum), over 4000 m above the sea level, southwest China, Aug.
Specimen examined: CHINA. YUNNAN PROVINCE: Deqin County, Baima Snow Mountain National Nature Reserve, alt. 4408 m, 21 Aug 2018, S. P. Jian 225 (KUN-HKAS104520).
Fig 1. Phylogenetic relationships among representative specimens of Clitopilus, Clitocella, and Clitopilopsis inferred from a multigene (28S, rpb2, tef1, and atp6) data set using both ML and BI methods (only the ML tree is shown). Bootstrap frequencies (>50%) and posterior probabilities (PP > 0.90) are shown on the supported branches. Sequences from type collections are marked, and altitude information of most specimens from KUN-HKAS is shown in the phylogram. New taxa are highlighted in red.