Panaeolus cinctulus Sacc.

Panaeolus cinctulus (Bolton) Sacc., Syll. fung. (Abellini) 5: 1124 (1887) Fig. 5 Basionym. Agaricus cinctulus Bolton 1792 Description. Pileus 7.0– 26.5 mm in diam., parabolic, obtusely conic, gray (pantone warm gray 1 c), light brown (pantone 4665 c), glabrous, surface dry, smooth, disc could be darker as light brown, margin straight or slightly decurved. Lamellae adnate, close, broad, mottled grayish to blackish, entire, white edge not distinctive. Stipe equal, hollow, 42.1–75.3 mm long, 1.4–2.6 mm thick, the same color as pileus, smooth, surface silk-like, longitudinally striate, especially on the upper side, base with whitish mycelium. Basidiomes getting brown when handling, bruising, and cutting. Basidiospores 11.3–12.5 × 7.8–9.2 μm, [x = 11.8 ± 0.3 × 8.7 ± 0.3, Q = 1.3–1.5, Q m = 1.4 ± 0.1, n = 20], ellipsoid, blackish brown when mature, smooth, thick wall with germ pore. Basidia 20.7–25.8 × 9.7–12.8 μm, 4 - spored, smooth, hyaline. Cheilocystidia 23.7–41.5 × 7.2–10.5 μm, narrowly clavate, with a slightly inflated head and base, thin wall, hyaline, smooth. Pleurocystidia absent. Pileocystidia not observed. Caulocystidia 14.0–46.3 × 4.0–9.3 μm, cylindrical, hyaline, slightly flexuose. Habitat. Grows in grassland. Psilocybin-producing. Producing (ZRL 20200005, see Suppl. material 1: fig. S 7). Notes. According to the results of the phylogenetic analyses, P. cinctulus is clustered in subclade A 2 and is sister to the sequestrate species P. nirimbii. Morphologically, our samples exhibit smaller basidiomes (pileus 7.0– 26.5 mm in diam.) and a paler pileus compared with the original description of P. cinctulus (Saccardo 1887) and the description provided by Stamets (1996). Specimens examined. China. Inner Mongolia Autonomous Region: Baotou, Olympics Park, 13 June 2019, Jian-Yu Zhang, ZRL 20191912; Beijing: Chaoyang District, Olympics Park, 19 July 2020, Rui-Lin Zhao, ZRL 20200005; Ningxia Hui Autonomous Region: Yinchuan, 11 September 1995, Xiaolan Mao, Cangkuan Wang, HMAS 63178.