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

Gelatinostereum S.H. He, S.L. Liu & Y.C. Dai , gen. nov. MB 843417 View Materials .

Etymology: The genus epithet “ Gelatinostereum ” refers to the gelatinous and stereoid basidiomes; “ Gelatino -”: from gelatinous; “ stereum ”: from the genus Stereum .

Basidiomes annual, resupinate to effused-reflexed, adnate, separable, gelatinous, hygrophanous, soft when fresh, becoming ceraceous to cartilaginous, brittle after drying. Pilei small, often radiately plicate, with abhymenial surface glabrous, light brown, golden brown to dark brown, indistinctly zonate and sulcate. Hymenophore smooth, tuberculate to merulioid, greyish orange, brownish orange, light brown to brown, 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. Hyphal system dimitic. Generative hyphae simple-septate, colourless, thin- to thick-walled with a wide lumen, smooth, rarely branched, moderately septate. Skeletal hyphae colourless, distinctly thick-walled, smooth, unbranched, not septate, with walls swelling in KOH. Gloeocystidia numerous, tubular, subclavate or subulate, colourless, thin-walled, smooth, embedded. Hyphidia numerous, unbranched, colourless, thin- to slightly thick-walled, smooth. Basidia clavate, colourless, thin-walled, smooth, with four sterigmata and a basal septum. Basidiospores cylindrical to suballantoid, colourless, thin-walled, smooth, amyloid, acyanophilous.

Type species: Gelatinostereum phlebioides S.H. He, S.L. Liu & Y.C. Dai

Notes: Gelatinostereum is similar to Stereum by sharing effused-reflexed basidiomes, a dimitic hyphal system with simple-septate generative hyphae and smooth amyloid basidiospores but differs in having gelatinous and brittle basidiomes with a smooth to merulioid hymenophore and thickened subhymenium, thin-walled gloeocystidia and numerous hyphidia. In the phylogenetic tree, Gelatinostereum formed a sister lineage to Stereum with high support values (90/91/1, Fig. 1 View Fig ).