Gelatinostereum phlebioides S.H. He, S.L. Liu & Y.C. Dai, 2025

Gelatinostereum phlebioides S.H. He, S.L. Liu & Y.C. Dai , sp. nov. MB 843418 View Materials . Figs 5 View Fig , 6 View Fig .

Etymology: The species epithet “ phlebioides ” refers to the phlebia-like hymenophore when fresh.

Typus: China, Guizhou Province, Jiangkou County, Fanjingshan Nature Reserve ,on fallen trunk of Rhododendron , 24 Nov. 2014, Y.C. Dai, Dai 14965 (holotype BJFC 018078 About BJFC , isotypes in BJM, CFMR) .

Basidiomes annual, resupinate to effused-reflexed, adnate, separable, gelatinous, hygrophanous, soft when fresh, becoming ceraceous to cartilaginous, brittle after drying, up to 30 cm long, 5 cm wide, 500 µm thick. Pilei small, often radiately plicate; abhymenial surface glabrous, light brown, golden brown to dark brown, indistinctly zonate and sulcate. Hymenophore smooth, tuberculate to merulioid, greyish orange [5B(3–6)], brownish orange [5C(4–6)], light brown [5D(4–8)] to brown [5E(4–8)], slightly darkening in KOH, uncracked or densely cracked with age; margin determinate, abrupt, adnate or slightly elevated and curved towards the hymenophore, white when juvenile, slightly paler or concolourous with hymenophore when mature. Context brownish orange, with a compact and agglutinated texture, up to 0.4 mm thick. Hyphal system dimitic; all hyphae without clamps. Subiculum distinct, with a compact texture, composed of tightly agglutinated and parallelly arranged hyphae; generative hyphae colourless, thin- to thick-walled with a wide lumen, smooth, rarely branched, moderately septate, 3–4.5 µm diam. Skeletal hyphae colourless, distinctly thick-walled, smooth, unbranched, not septate, with walls swelling in KOH, 4–6 µm diam. Subhymenium thickening with age; generative hyphae colourless, thin-walled, smooth, interwoven, agglutinated, 2–4 µm diam. Gloeocystidia numerous, tubular, subclavate or subulate, colourless, thin-walled, smooth, mostly embedded, (35–)60– 130 × 7–12(–14) µm. Hyphidia numerous, colourless, thinto slightly thick-walled, smooth, 25–35 × 2–3.5 µm. Basidia clavate, colourless, thin-walled, smooth, with four sterigmata and a basal septum, 20–40 × 4–5.5 µm. Basidiospores cylindrical to suballantoid, colourless, thin-walled, smooth, amyloid, acyanophilous, (5.5–)6–7.8(–8.3) × 2–3(–3.8) µm, L = 6.8 µm, W = 2.6 µm, Q = 2.6–2.7 (n = 90/3).

Additional specimens examined: China, Fujian Province, Wuyishan County, Wuyishan Nature Reserve , on dead branch of Rhododendron , 17 Aug. 2016, S. H . He, He 4492 ( BJFC 023933 About BJFC ) ; Jiangxi Province, Lianping County, Jiulianshan Nature Reserve, On dead branch of Rhododendron , 14 Aug. 2016, S. H . He, He 4383 ( BJFC 023824 About BJFC ) ; Yunnan Province, Jingdong County, Ailaoshan Nature Reserve, On dead branch of Rhododendron , 15 Oct. 2013, S. H . He, He 1951 ( BJFC 016419 About BJFC ); Yulong County, Laojunshan Nature Reserve , on fallen trunk of Rhododendron , 1 Sep. 2015, S. H . He, He 2918 ( BJFC 021348 About BJFC ); Fuyuan County, Shibalianshan Nature Reserve , on dead branch of Rhododendron , 19 Nov. 2019, S. H . He, He 6340 ( BJFC 033284 About BJFC ) .

Notes: Gelatinostereum phlebioides is the only species in the genus so far. It is similar to species of Stereum s. str., which, however, differs in non-gelatinous basidiomes and thick-walled gloeocystidia.