Panaeolus semiovatus S. Lundell & Nannf.

Panaeolus semiovatus (Sowerby) S. Lundell & Nannf., Fungi Exsiccati Suecici 11–12 (Sched.): 14 (no. 537) (1938) Fig. 12 Basionym. Agaricus semiovatus Sowerby Description. Pileus 7–41 mm in diam., ovoid when young, then parabolic (half-egg), surface dry, smooth (could be cracked where habitat is dry), glabrous, with light color from white to bright brown (pantone 4655 c), margin straight. Lamellae adnate, close, entire, broad, mottled grayish first then becoming blackish when mature, with a white edge. Stipe equal, hollow, 17–110 mm long, 1–7 mm thick, with some color as pileus, smooth, base occasionally could be brown, always with whitish mycelium. Annulus always remaining still mature, membranous, white, medium. Basidiospores 18.9–22.3 × 10.9–12.6 μm, [x = 20.8 ± 0.9 × 11.7 ± 0.5, Q = 1.7–2.0, Q m = 1.8 ± 0.1, n = 20], ellipsoid, elongate, blackish brown when mature, smooth, thick wall, germ pore distinctive. Basidia 30.7–41.0 × 11.5–21.3 μm, 4 - spored, smooth, hyaline. Cheilocystidia 26.6–39.4 × 8.1–20.8 μm, with virous shapes, clavate with a slightly narrow apex, Y-shaped, pyriform, hyaline, smooth. Pleurocystidia absent. Cuticle composed of large vesicles, pileocystidia not observed. Caulocystidia not observed. Habitat. Grows in pastures, on dung of horses and cows. Psilocybin-producing. Nonproducing (ZRL 20201278, see Suppl. material 1: fig. S 2). Notes. Panaeolus semiovatus is characterized by its medium- to large-sized basidiomes, a parabolic and glabrous pileus of light color, and a permanent annulus that persists at maturity. These characteristics make it a morphologically distinctive species in the wild, especially because of its large-sized basidiomes. Specimens examined. China. Sichuan Province: Tibetan Autonomous Prefecture of Garzê, Batang County, Cuopugou, 20 July 2015, Mao-Qiang He, ZRL 2015429; Zhubalong Natural Reserve, 29°39'39.48"N, 99°5'37.68"E, alt. 4311 m, 19 August 2020, by Xin-Yu Zhu, Xi-Xi Han, ZRL 20201190, ZRL 20201375; Litang County, Zhaga Mountain, 20 August 2020, Xi-Xi Han, Bin Cao, ZRL 20201260, ZRL 20201261, ZRL 20201278; Nuoergai County, 13 September 1992, Xiaolan Mao, HMAS 61642; Gansu Province: Zhangye, Sunan County, Kangle, 27 August 2018, Ming-Zhe Zhang, ZRL 20181933; Beijing: Fangshan District, Baicaopan Nature Park, 1 August 2019, Rui-Lin Zhao, ZRL 20190162; Xizang Autonomous Region: Nyingchi Municipality, Mêdog County, Xironggou, 29.42.33°N, 95.35.8°E, alt. 2800 m, 25 July 2021, Bin Cao, ZRL 20210938, ZRL 20210939; 28°36'26"N, 98°6'11"E, alt. 3848 m, ZRL 20231351; Shigatse Municipality, Yadong County, 27.25.20°N, 88.55.6°E, alt. 3254, 27 July 2022, Mao-Qiang He, ZRL 20220286; Jilin Province: 2 September 1992, Zongliu Chen, Suxiao Sun, HMAS 59847; Xinjiang Uygur Autonomous Region: 10 August 1985, Li Fan, Yumei Li, HMAS 86009; Qinghai Province: Beishan National Forestry Park, 36°55'41"N, 102°26'7"E, alt. 2427 m, 9 July 2023, Mao-Qiang He, ZRL 20230570, ZRL 20235586, ZRL 20235598, ZRL 20235619; 38°3'13"N, 100°23'54"E, alt. 3297 m, 29 August 2023, Mao-Qiang He, ZRL 20235824.