Pseudohydnum sinogelatinosum Y. C. Dai, F. Wu & H. M. Zhou

Pseudohydnum sinogelatinosum Y. C. Dai, F. Wu & H. M. Zhou, J. Fungi 8 (7, no. 658): 7 (2022) Fig. 8 Description. Basidiomata large-sized, gelatinous when fresh, pileate, laterally stipitate, solitary or gregarious (often confluent at the base). Pileus up to 60 mm in widest diameter and 15 mm thick, flabellate or semicircular; pileal surface smooth to minutely velutinous or strigose, varying from pale grayish white, pale clay-pink to sorrel brown, translucent when fresh; margin blunt, entire, undulating, fertile. Hymenophore hydnoid; spines sharp-tipped, 1–5 mm long, 1–3 per mm, white to milk white. Stipe 10–25 mm long, 10–17 mm in diam., lateral, watery-grayish to pale grayish white, subcylindrical to slightly compressed, translucent; surface minutely velutinous to strigose or partially bearing spines. Context gelatinous, translucent, unchanging. Odor and taste mild. Basidiospores [60 / 3 / 2] (7.0 –) 7.2–8.8 (– 9.2) × (6.2 –) 6.7–8.2 (– 8.5) μm, Q = (1.02 –) 1.03–1.24 (– 1.27), Qm = 1.11 ± 0.06, globose to broadly ellipsoid, hyaline, smooth, thin-walled, nonamyloid, with a small apiculus, frequently germinating by repetition or by germ tubes. Basidia 12–14 × 9–12 μm, longitudinally cruciate-septate, predominantly 4 - spored, occasionally 2 - spored, arranged in a dense palisade extending to the spine apices; sterigmata up to 14 × 2–4 μm. Hyphidia 1–3 μm in diam., common, branched, with simple septa or clamp connections. Hyphal system monomitic, generative hyphae with clamp connections. Pileipellis composed of subparallel or ascending hyphae, 1–4 μm in diam., occasionally inflated up to 11 μm, thin- or slightly thick-walled, hyaline to brownish. Contextual hyphae 1-7 μm in diam., rarely inflated up to 14 μm in diam., interwoven, thin- to slightly thick-walled, hyaline. Subhymenial hyphae hyaline, thin-walled, interwoven or anastomosing, 1–5 μm in diam., occasionally inflated up to 13 μm. Ecology and distribution. Growing on decayed coniferous wood (Abies, Pinus, and Picea spp.). Currently known only from Sichuan, Xizang, and Yunnan, southwestern China. Specimens examined. China • Yunnan Province, Deqin County (德钦县), Yunling Town (云岭乡), 28°23'40"N, 098°48'23"E, elev. 3,255 m, 14 August 2016, leg. Y. Li (HMAS 277542); • Ninglang County (宁蒗县), en route from Gewa Village (格瓦村) to Labo Town (拉伯乡), 27°43'25"N, 100°31'56"E, elev. 3,440 m, on decaying Picea wood, 1 October 2023, leg. T. J. Yu (MHKMU YTJ 185); • Shangri-la City (香格里拉市), near Yijia Village (彝族村), 27°23'11"N, 100°06'30"E, elev. 3,180 m, from decaying Pinus wood, 26 August 2020, leg. X. Na (MHKMU NX 221); • ibid., near Yijia Village (彝族村), on decaying Pinus wood, 29 July 2021, leg. W. H Zhang (MHKMU ZWH 647); • ibid., near Yijia Village (彝族村), 27°23'14"N, 100°06'31"E, elev. 3,170 m, on decaying Pinus wood, 26 August 2020, leg. L. P Tang (MHKMU TLP 3439). Comments. Pseudohydnum sinogelatinosum is one of the most common representatives of the genus in subalpine regions of the Himalayas, where it occurs on decayed wood of Abies, Picea, and Pinus (Zhou et al. 2022; Wang et al. 2025). Previous reports suggested that this species has a predominantly pale-colored pileus. In contrast, our observations reveal an unexpectedly high degree of morphological variability: pileus color ranges extensively, from white, grayish white, pale brown, brown, dark brown, cinnamon, to clay-pink, and the pileus surface varies from smooth to densely covered with minute spines. These findings document considerable intraspecific morphological variation in P. sinogelatinosum across its geographic range and underscore the necessity of molecular data for accurate species identification when morphology alone is insufficient.