Panaeolus medogensis M. Q. He & R. L. Zhao sp. nov. Fig. 9 Etymology. medogensis (Lat.) refers to the type locality, Mêdog County, in the Xizang Autonomous Region of China. Diagnosis. Panaeolus medogensis has small basidiomes with glabrous and rugulose pileus and narrowly clavate cheilocystidia with inflated base. Holotype. CHINA. Xizang Autonomous Region: Nyingchi Municipality, Mêdog County, 29.47.30°N, 95.41.50°E, alt. 3670 m, 24 July 2021, Mao-Qiang He, HMAS 287498 (ZRL 20210733). Description. Pileus 7.6–17.6 mm in diam., parabolic, light gray (pantone 427 c), light brown (pantone 4685 c), brown (pantone 4645 c), color radially getting paler from disc to margin, glabrous, surface dry, smooth, rugulose especially in / around the disc, margin straight or slightly decurved. Lamellae adnate, subdistant, broad, mottled grayish to blackish, entire, edge white. Stipe equal, hollow, 24.1–47.3 mm long, 1.6–2.6 mm thick, brown, the same color as pileus, longitudinally striate, some pruinose, base with whitish mycelium. Basidiomes getting brown when handling, bruising, and cutting. Basidiospores 13.2–15.0 × 9.2–11.4 μm, [x = 13.9 ± 0.5 × 10.3 ± 0.6, Q = 1.2–1.5, Q m = 1.4 ± 0.1, n = 20], ellipsoid, limoniform, brown, thick wall with germ pore. Basidia 29.7–40.0 × 11.4–14.5 μm, 4 - spored, smooth, hyaline. Cheilocystidia 23.1–35.9 × 4.2–8.7 μm, narrowly clavate, with an inflated base, slightly flexuose, hyaline, smooth. Pleurocystidia 22.4–37.7 × 10.7–14.1 μm, clavate, hyaline. Pileocystidia not observed. Caulocystidia 32.0–72.2 × 3.7–11.9 μm, long clavate, hyaline, some slightly flexuose. Habitat. Grows on fertile soil as pastures, grasslands, and forests. Psilocybin-producing. Nonproducing (ZRL 20210733, see Suppl. material 1: fig. S 13). Notes. Panaeolus medogensis was found in a grazing area that is also a forest edge with lush grasses. According to the results of the phylogenetic analyses, P. medogensis is sister to P. limoniformisporus. Morphologically, the two species can be distinguished by the pileus. Compared with other species in Panaeolus, P. medogensis is characterized by its small-sized basidiomes with a brown, glabrous, and rugulose pileus.

Published as part of He, Mao-Qiang, Yang, Wen-Qiang, Phurbu, Dorji, Liu, Fei, Li, Jia-Xin, Cao, Bin & Zhao, Rui-Lin, 2026, Systematic study of Panaeolus (Agaricales, Galeropsidaceae) sensu lato and psilocybin-producing traits of species from China, pp. e 167329 in IMA Fungus 17 on page e167329, DOI: 10.3897/imafungus.17.167329