Spodocybe umbilicata Z.M. He, Hai J. Li, S.N. Li, P. Zhang & Z.H. Chen, 2023

Xiao, Ying-Qun, Li, Hai-Jiao, Li, Sai-Nan, Chen, Zuo-Hong, Zhang, Ping & He, Zheng-Mi, 2023, Spodocybe umbilicata (Hygrophoraceae, Agaricales), a newly discovered species from subtropical China, Phytotaxa 620 (4), pp. 273-282 : 277-279

Spodocybe umbilicata Z.M. He, Hai J. Li, S.N. Li, P. Zhang & Z.H. Chen , sp. nov. ( Figs. 3 and 4 )

MycoBank: MB849167

Etymology:—“ umbilicata ” (Latin), referring to the umbilicate pileus.

Diagnosis:—This species exhibits an umbilicate, greyish brown pileus with finely felty texture, a stipe of the same color, white decurrent lamellae, and elongate to cylindrical basidiospores. It can be easily distinguished from the closely related species Spodocybe bispora by its 4-spored basidia.

Type:— CHINA. Hunan Province: Ningxiang County, Ziquan Village , on humus, in a bamboo forest, alt. 115 m, at 28.209067°N, 112.295692°E, 20 November 2018, collected by S.N. Li, P. Zhang and Z.H. Chen, MHHNU 31388 (holotype!) .

Gene sequences ex-holotype:—OQ301569 (ITS); OQ299517 (LSU); OQ302547 (TEF1); OQ302540 (RPB1); OQ302543 (RPB2); OQ302551 (ATP6).

Description:— Fruitbody small-sized, clitocyboid to omphalinoid. Pileus 10–30 mm in diam, umbilicate; surface not hygrophanous, finely felty, greyish brown (5D2–4); margin not striate, often reflexed; center not gibbous, darker in color; context thin (1–2 mm thick), white (1A1). Lamellae decurrent, subdistant, white (1A1), narrow (up to 2 mm high), rarely furcate; edges smooth. Stipe 10–30 × 2–5 mm, central, equal, often flexuous; surface finely whitefibrillose longitudinally, concolorous with pileal surface; base not inflated, with white tomentum and a few rhizoids; context white (1A1). Odor fungoid and pleasant.

Basidiospores [60/3/2] (5.5)6.0–9.0(9.5) × 3.0–4.5 μm, Q = (1.56)1.64–2.21(2.35), Qm = 1.90 ± 0.18, elongate to cylindrical, with broad (1.0–1.5 μm across) obtuse or acute bases, sometimes somewhat lacrymoid, smooth, hyaline, thin-walled, inamyloid, some of them occurring in tetrads. Basidia 22.0–33.0 ×5.0–6.0 μm, clavate, hyaline, thin-walled, 4-spored; sterigmata up to 6.0 μm long. Pleurocystidia and cheilocystidia absent. Lamellar trama subregular; hyphae 2.5–8.0(10.0) µm wide, hyaline, cylindrical, thin-walled, septate, not branched. Pileipellis a cutis, composed of subparallel to interwoven, thin-walled, cylindrical hyphae 2.5–8.0 μm wide, with short outgrowths and branches, as well as exserted ends, producing brown intracellular pigment. Stipitipellis a cutis, composed of thin- to slightly thickwalled (up to 0.4 μm) hyphae, 2.0–5.0 μm wide. Clamp connections present in all tissues.

Ecology:—Usually gregarious in clusters of 2–5 basidiomes, on decaying fallen leaves or needles, in subtropical forests; autumn.

Distribution:—Known from Central and Southwestern China, also in Japan ( Voyron et al. 2022).

Additional specimen examined:— CHINA. Yunnan Province: Zhenxiong County, Shangjie Village , on needle litter of Cunninghamia lanceolata (Lamb.) Hook. , alt. 1700 m, at 27.442536°N, 104.868422°E, 19 October 2022, collected by X.D. Fan, YNZX20221019-02 ( MHHNU 33806 ) .

Figures

FIGURE 3. Spodocybe umbilicata. A Fresh basidiomes, MHHNU 31388 (holotype), photographed by Zuo-Hong Chen; B Dried basidiomes, MHHNU 33806, photographed by Hai-Jiao Li. Bars = 2cm.

FIGURE 4. Microscopic features of Spodocybe umbilicata (MHHNU 31388, holotype). A Basidiospores and basidia; B Pileipellis. Bars = 10 μm, drawn by Zheng-Mi He.