Panaeolus limoniformisporus M. Q. He & R. L. Zhao, sp. nov.

Panaeolus limoniformisporus M. Q. He & R. L. Zhao sp. nov. Fig. 8 Etymology. limoniformisporus (Lat.) refers to the limoniform basidiospores. Diagnosis. Panaeolus limoniformisporus has gray basidiomes with conic, hygrophanous pileus and limoniform basidiospores. Holotype. CHINA. Gansu Province: Wuwei, Tianzhu County, Kela, 19 August 2018, Zhi-Lin Ling, HMAS 287497 (ZRL 20181122). Description. Pileus 13.1–39.9 mm in diam., conic, parabolic, background gray (pantone cool gray 1 c) to light brown (pantone 4685 c), surface dry, smooth, mottled, and radially streaked by blackish brown (pantone 7533 c) hygrophanous stripes, also could be totally white or light brown without radial stripes, margin slightly exceeding gills. Lamellae adnate, sub-close, broad, mottled grayish to blackish, entire, with a white edge. Stipe equal, hollow, 74.9–108.6 mm long, 1.9–5.0 mm thick, white, longitudinally striate, especially on the upper side, base with whitish mycelium, getting darker when handling. Basidiospores 13.7–15.1 × 10.0–11.3 μm, [x = 14.3 ± 0.4 × 10.7 ± 0.4, Q = 1.3–1.4, Q m = 1.3 ± 0.0, n = 20], limoniform, blackish brown, smooth, thick wall with germ pore. Basidia 24.1–28.9 × 12.6–14.9 μm, 4 - spored, smooth, hyaline. Cheilocystidia 23.6–40.5 × 4.2–9.9 μm, narrowly cylindrical, flexuose, with a slightly inflated base, hyaline, smooth. Pleurocystidia 21.4–27.5 × 10.7–13.8 μm, spheropedunculate, hyaline. Pileocystidia not observed. Caulocystidia not observed. Habitat. Grows in pastures and on soil. Psilocybin-producing. Nonproducing (ZRL 20181122, see Suppl. material 1: fig. S 12). Notes. Panaeolus limoniformisporus is revealed to be the sister species of P. medogensis (Figs 2, 3). Morphologically, both species form small-sized basidiomes, but the pileus differs between them: the pileus of P. limoniformisporus is gray, black, or white, slightly fibrillose, and hygrophanous, whereas the pileus of P. medogensis is brown and glabrous. Specimens examined. China. Sichuan Province: Tibetan Autonomous Prefecture of Garzê, Batang County, 20 July 2015, Mao-Qiang He, ZRL 2015390; Yajiang County, Gexi Natural Reserve, 15 August 2020, Mao-Qiang He, ZRL 20200165; Xizang Autonomous Region: Nyingchi Municipality, Nang County, 19 September 2015, Xu-Ming Bai, ZRL 20152331; Gansu Province: Wuwei, Tianzhu County, Kela, 19 August 2018, Zhi-Lin Ling, ZRL 20180975; Shigatse Municipality, Gyirong County, Gyirong Town, 28.22.39°N, 85.19.40°E, alt. 2780 m, 02 August 2022, Mao-Qiang He, ZRL 20220678.