Confertotrama Nakasone & S. H. He 2025, gen. nov.

Confertotrama Nakasone & S.H. He, gen. nov. MB 843412. Etymology: The genus epithet “ Confertotrama ” refers to the compact and agglutinated context. Basidiomes annual, resupinate, effused, closely adnate, subceraceous to crustose. Hymenophore smooth or tuberculate, yellow, orange to ochraceous, uncracked or densely cracked with age; margin determinate, abrupt or thinning out, sometimes loosening from the substrate, paler or concolourous with hymenophore. Context yellowish white, with compact and agglutinated texture. Hyphal system monomitic; all hyphae with clamps, colourless, thin- to slightly thick-walled, smooth, rarely branched, moderately septate. Gloeocystidia numerous, vesicular, tubular to subulate, large, thin- to thick-walled, smooth, often with yellowish contents, turning bluish black in sulphovanillin, embedded or slightly projecting beyond the hymenium. Basidia clavate, colourless, thin-walled, smooth, with four sterigmata and a basal clamp. Basidiospores ellipsoid, oblong ellipsoid to cylindrical, colourless, thin-walled, smooth or ornamented, distinctly amyloid, acyanophilous. Type species: Confertotrama rugulosa (Berk. & M.A. Curtis) Nakasone & S.H. He Notes: Larsson & Larsson (2003) indicated that Megalocystidium chelidonium, Boidinia macrospora, Gloeocystidiellum aspellum, Gm. compactum and Gm. formosanum formed a strongly supported lineage (/ chelidonium) in Stereaceae. Our phylogenetic analyses also recovered this lineage (Fig. 1). Morphologically, these species have some similar characteristic features, such as yellowish basidiomes with compact texture, clamped generative hyphae and numerous large gloeocystidia with a positive sulphovanillin reaction. Basidiospores are reported as smooth in M. chelidonium and verrucose to indistinctly verrucose in the other species (Wu 1996, Boidin et al. 1997). Since there are no other morphological characters that can be used to separate M. chelidonium from other species in this lineage, we treat the lineage as a single genus and propose the new generic name Confertotrama.