A new wood-decaying fungus, Sertulicium asiae-orientalis (Sistotremastrales, Basidiomycota), from East Asia

Wood-decaying fungi constitute a critical ecological group within forest ecosystems, playing a significant role in lignocellulose decomposition and nutrient cycling. This study describes a new corticioid species, Sertulicium asiae-orientalis sp. nov., based on both morphological characteristics and phylogenetic analyses. Three specimens were collected from northeast China and examined alongside sequence data from an additional specimen originating in the Khabarovsk Region of Russia. Phylogenetic analyses of combined ITS and nLSU sequence data indicate that these four specimens form a distinct lineage within Sertulicium, closely related to S. niveocremeum and S. lateclavigerum. The new species is distinguished by annual, resupinate basidiomata with a white to gray, pruinose to reticulate hymenial surface; a monomitic hyphal system with clamped generative hyphae; absence of cystidia and hyphidia; clavate basidia (12–19 × 4–6 μm); and narrowly ellipsoid to cylindrical basidiospores (4.5–6.6 × 2.3–2.9 μm). The identification of S. asiae-orientalis increases the number of recognized Sertulicium species to nine and underscores the insufficiently explored diversity of wood-decaying fungi in East Asia.