Clitopilus umbilicatus 2020

Clitopilus umbilicatus S.P. Jian & Zhu L. Yang, sp. nov. 2020

MycoBank MB831312

Holotype: CHINA. ANHUI PROVINCE: Qianshan County, Shuihou Town, Longxing Hamlet, in groups, growing on slope with moss in coniferous (Pinus massoniana Lamb.) and broad-leaved (Fagaceae) mixed forests, alt. 80 m, 28 Jun 2013, L.H. Han 79 (holotype KUN-HKAS80310).

Morphological description

Basidiomata infundibuliform or omphaloid, sometimes clitocyboid, small to mediumsized. Pileus 5–50 mm wide, plano-concave to infundibuliform, often deeply depressed at center; surface whitish (4A1) to yellowish white (1A2–3), usually minutely tomentose or smooth; margin slightly incurved to incurved, then straight, even or undulate; context very thin, 0.5–2 mm thick, white (3A1). Lamellae decurrent, white (1A1) to yellowish pink (2A3), somewhat crowded to crowded, up to 1.5 mm in height, edges entire and concolorous, fragile, lamellulae numerous. Stipe 7–40 × 2–6 mm, eccentric, rarely central or lateral, subcylindrical, usually concolorous with pileus, smooth or minutely pruinose; the base sometimes with white (1A1) mycelium. Odor strongly farinaceous.

Basidiospores (4–)5–7 × (3.5–)4–5(–5.5) μm, L_m ×

W_m = 5.42 (± 0.47) × 4.51 (± 0.38) μm, Q = (0.89–) 1.00–1.52(–1.56) (Q_avg = 1.21 ± 0.13) [132/6/6], nearly hyaline, globose to subglobose, broadly ellipsoid to ellipsoid in profile and face view, nearly smooth or angled in polar view with 8–10 inconspicuous or obscure longitudinal ridges. Basidia 14–29 × 7–9 μm, clavate, hyaline, 4-spored, rarely 2-spored; sterigmata 3–5 μm. Lamellar trama more or less regular, composed of 3–11 μm wide, hyaline hyphae; oleiferous hyphae present, up to 100 μm in length and 2–4 μm wide; subhymenium composed of 2–5 layers of globose, subglobose to ovoid hyphal segments, 3–13 × 3–10 μm.

Lamellae edges fertile. Pleurocystidia and cheilocystidia absent. Pileipellis a cutis composed of more or less radially arranged, repent, hyaline, smooth, cylindrical hyphae, 3–6 μm wide, sometimes mixed with long oleiferous hyphae, 50–100 μm in length, 4–13 μm wide; subcutis made up of compactly arranged, thinwalled, hyaline, smooth, cylindrical hyphae, 4–13 μm wide, with oleiferous hyphae; pileal trama composed of subregular, hyaline, oblong-ovoid, inflated hyphae, 4–20 μm wide, with many oleiferous hyphae, up to 250 μm in length. Stipitipellis a cutis composed of compactly arranged, thin-walled, hyaline hyphae, 3–6 μm wide; oleiferous hyphae also present. Caulocystidia absent. Clamp connections absent.

Habitat: on slope with moss in coniferous (Pinus massoniana Lamb.) and broad-leaved (Fagaceae) mixed forests.

Distribution: southeast to southwest China.

GenBank Accession: ITS MN061324; 28S MN065716; rpb2 MN148153; tef1 MN166263; atp6 MN133772

Notes: In sect. Crispi, C. umbilicatus is similar to C. chalybescens T.J. Baroni & Desjardin and C. peri. Clitopilus chalybescens, originally described from Thailand, and differs from C. umbilicauts by the grayish blue discolorations of the pileus and the presence of caulocystidia (Baroni et al. 2001). Clitopilus umbilicatus could be confused with C. peri, but the latter has smaller basidiomata and larger ellipsoid basidiospores (Pegler 1977a, 1977b; Baroni and Watling 1999).

Reference: Si-Peng Jian, Tolgor Bau, Xue-Tai Zhu et al. (2020): Clitopilus,Clitocella, and Clitopilopsis in China.

Basidiomata of Clitopilus, Clitocella, and Clitopilopsis. A–C. Clitopilus umbilicatus (A. KUN-HKAS80370. B. KUN-HKAS104509. C. KUN-HKAS80310, holotype). D–E. Clitopilus yunnanensis (D. KUN-HKAS59712. E. KUN-HKAS82076). F. Clitocella mundula (HMJAU7275). G–H. Clitocella orientalis (G. KUN-HKAS78876. H. KUN-HKAS78763, holotype). I. Clitopilopsis albida (KUN-HKAS104519, holotype). Bars = 10 mm