Ripartites subtropicus (Paralepistaceae, Agaricales), a newly discovered species from subtropical China Yang, Yu-Zhi Deng, Peng-Tao Yan, Jun Xiao, Ying-Qun Zhang, Ping Chen, Zuo-Hong He, Zheng-Mi Phytotaxa 2025 2025-06-11 705 1 50 62 Z.M. He & Y.Z. Yang Z. M. He & Y. Z. Yang 2025 [136,641,1236,1263] Agaricomycetes Tricholomataceae Ripartites Fungi Agaricales 4 54 Basidiomycota species subtropicus sp. nov.  Etymology:— ‘ subtropicus’ (Latin), referring to the subtropical habitat. Diagnosis:—This species has a white to light brown depressed pileus with finely pubescent margin, cream decurrent lamellae, a yellow-brown stipe with basal rhizoids, and verrucose basidiospores. Similar to  R. tricholoma, but differs by its nearly naked to indistinct pubescent pileus margin, the concurrent presence of mono-, bi- and tetrasporic basidia, and its subtropical habitat. Type:— CHINA. Guizhou Province: Shuicheng County, Shuicheng National  RhododendronGarden, on humus covered with needle litter of  Pinus armandiiFranch., alt. 1982 m, at 26°47'34.82''N, 104°49'4.63''E, 17 June 2023, Z.M. He 1, MHHNU 20001 ( holotype!). Description:— Fruitbodysmall-sized, omphalioid. Pileus 10–30 mmin diam, applanate to slightly depressed with an unconspicuous papilla at center, hygrophanous; surface white (1A1) when dry, light brown (3A2–3) when wet, yellowish brown (5A2–4) at center, smooth, not gelatinized; margin inflexed to involute when young, straight when old, finely white (1A1) pubescent at very margin, not striate; context thin ( 1–2 mmthick), white (1A1). Lamellaedecurrent, subcrowded, sometimes furcate near stipe apex, arcuate, cream (1A2), narrow ( 1–2 mmhigh); edges even. Stipe14–35 × 2–3 mm, central or somewhat eccentric, solid, equal, often flexuous; surface wet, yellow-brown (3B4– 6), finely white-fibrillose longitudinally; base not inflated, with white (1A1) rhizomorphs; context white (1A1). Odorfungoid and pleasant. Chemical spot test:surface of dried pileus and stipe produces a negative reaction to 30% KOH.  Basidiospores[100/3/3] (4–)4.5–5.5 × 4–5 μm, Q = (1.02–)1.04–1.23(–1.28), Qm = 1.13 ± 0.06, pale brown, subglobose to broadly ellipsoid, with verrucae 0.4–0.6 × 0.3–0.4 μm, thin-walled, inamyloid. Basidia20–27 × 6–9 μm, clavate, hyaline, thin-walled, 1-, 2- or 4-spored; sterigmata up to 9 μm long. Pleurocystidiaand cheilocystidiaabsent. Lamellar tramasubregular, composed of thin-walled, cylindrical, non-branched hyphae 4–10 µm wide. Pileipellisa cutis, composed of parallel to slightly interwoven, thin-walled, cylindrical hyphae 3–6 μm wide, with clusters of filamentous hyphae at margin. Stipitipellisa cutis, composed of parallel, thin-walled hyphae 4–8 μm wide. Clamp connectionspresent in all tissues.   FIGURE 1.ML analysis of  Ripartitesbased on ITS sequences, with  Paralepista flaccidaas outgroup. Bootstrap values (BP) ≥ 50% from ML analysis and Bayesian posterior probabilities (PP) ≥ 0.95 from BI analysis are shown at nodes. The type species of  Ripartitesis marked with a star. The sequences of the new taxon are highlighted in bold and the sequences of holotypes are indicated in blue. Ecology:—Solitary, on humus, in subtropical montane forests; summer. Distribution:—Only known from Southwestern and Central China.   FIGURE 2.Basidiomata of  Ripartites subtropicus. A, BMHHNU 20001 (holotype); C, DMHHNU 20017; E–GKUN-HKAS 77956. Bars = 1 cm, photographed by Zheng-Mi He, Ping Zhang, and Jiao Qin, respectively. Additional specimens examined:— CHINA. Hubei Province: Qingchuan County, southern district of Shennongjia Forestry, on humus covered with oak leaf litter, alt. 1800 m, at 31°24'54.14''N, 110°29'58.53''E, 16 July 2012, J. Qin 555, KUN-HKAS 77956. Guizhou Province: Leishan County, Leigong Mountain National Forest Park, on humus covered with leaf litter of  Pinus fenzelianaHand.-Mazzand  Fagussp., alt. 1730 m, at 26°22'36.81''N, 108°11'58.19''E, 21 June 2023, Z.M. He 17, MHHNU 20017.