Psilocybe zhushanensis R.L. Zhao & B. Cao, in Cao et al., Fungal Diversity 132: 541 (2025)
Index Fungorum number: IF 572498; Mycobank number: MB 572498; Facesoffungi number: FoF 17669; Figs. 1, 2
Etymology – refers to Zhushan County, Hubei Province, China, the locality of the type specimen.
Holotype – HMAS 282438.
Pileus 8–20 mm broad, convex to more-or-less hemispherical when young, becoming convex to pulvinate with a slight umbo or plane at center when mature, yellowish brown to orange brown, margin sometimes with a thin band of whitish veil remnants when young, often disappearing in age. Lamellae adnate to sinuate, relatively broad, buff to drab when young, become medium brown at maturity. Lamellulae present, 1–3 between each lamellum. Stipe up to 50 mm in length, central, smooth, fibrillose-striate, cylindric, equal, whitish to sorrel brown, solid or hollow, with white radiating rhizomorphs at the base. Context off-white.
Basidiospores (7.9–)8.3–8.8–9.2(–9.6) × (4.5–)4.8–5.1–5.3(–5.4) µm, Q = 1.6–1.7–1.9 (holotype, n = 30), ellipsoid to oblong, brown, thick-walled, with germ pore. Basidia 21.2–29.3 × 6.1–9.5 µm (holotype, n = 30), clavate. Pleurocystidia absent. Cheilocystidia 24.5–36.1 × 4.4–7.6 µm (holotype, n = 30), hyaline, thin-walled but sometimes with a gradually thickening wall toward apices, variable in shape, typically narrowly lageniform. Pileipellis constituted by cylindrical, radially arranged hyphae, 2.2–6.1 µm wide. Clamp connections present in all tissues.
Ecology – Gregarious, growing on decomposed wood.
Material examined – CHINA, Hubei Province, Shiyan City, Zhushan County, Duheyuan National Nature Reserve, 31°31’32.19”N 110°0’32.10”E, 1824 m asl, 28 August 2023, collected by Xin-Yu Zhu, ZRL20237000 (HMAS 282437) and ZRL20237017 (HMAS 282438, holotype).
GenBank – HMAS 282437: PV389794 (ITS); HMAS 282438: PV389795 (ITS).
Notes – In the BLAST analysis conducted on NCBI, the sequence most similar to Psilocybe zhushanensis was Psilocybe medullosa (Bres.) Borov. (GenBank HF912357), with a percent identity of 97.7%. We incorporated these similar sequences into the phylogenetic tree, and the results demonstrated that P. zhushanensis could be clearly distinguished from P. medullosa, forming an independent clade.
Figure 1 – Psilocybe zhushanensis (HMAS 282438, holotype). a, b Basidiomata. c, d Basidiospores. e Basidia. f Cheilocystidia. Scale bars: a–b = 1 cm, c, e = 5 µm, d, f = 10 µm.
Figure 2 – Maximum Likelihood tree of Psilocybe based on ITS sequences, bootstrap values greater than 50% are shown around nodes. New species are shown in red.