Lignosporidesmium H. W. Shen & Z. L. Luo 2026, gen. nov.

Lignosporidesmium H. W. Shen & Z. L. Luo gen. nov. Chinese name. 木葚孢属 (Pinyin: mù shèn bāo shǔ). Etymology. From ligno - (Latin lignum, “wood”), referring to its wood-inhabiting habit, and Sporidesmium, a related hyphomycetous genus. The name indicates a sporidesmium-like fungus occurring on woody substrates. Type species. Lignosporidesmium tropicale (M. B. Ellis) H. W. Shen & Z. L. Luo, comb. nov. Description. Saprobic on decaying wood substrates in freshwater and terrestrial habitats. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on superficial substratum, effuse, hairy, solitary or clustered, brown to black. Mycelium partly immersed and partly superficial, composed of septate, branched, pale to brown, smooth-walled hyphae. Conidiophores macronematous, mononematous, singly or in fascicles, unbranched, cylindrical, straight or slightly flexuous, septate, pale brown to dark brown, smooth and thick-walled. Conidiogenous cells monoblastic, terminal, integrated, percurrently proliferating, cylindrical, brown, smooth and thick-walled. Conidia acrogenous, solitary, pyriform, obclavate, rostrate, straight or slightly curved, euseptate, pale brown to dark brown, tapering to the apex, truncate at the base, thick-walled and verrucose, without sheath. Notes. Phylogenetic analyses recovered four strains of Lignosporidesmium tropicale (DLUCC 1689, HKUCC 10838, MFLUCC 16-0185 and N 58) forming a sister clade with Bullimyces communis (AF 281-5) and Ceratolenta caudata (CBS 125234) of Ceratolentales, although this relationship is not supported by stable statistical values. Morphologically, Lignosporidesmium tropicale differs from members of clades B, C, and D by possessing euseptate conidia, whereas taxa in these three clades are characterized by distoseptate conidia (Su et al. 2016; Yang et al. 2018; Luo et al. 2019; Bao et al. 2021; Crous et al. 2021 b; Delgado et al. 2025; Liu et al. 2025; Zhang et al. 2025 b). Furthermore, Lignosporidesmium is readily distinguished from species of clade A by its non-proliferating conidiogenous cells and pale brown to brown, obclavate, rostrate conidia; in contrast, species of clade A typically exhibit continuously proliferating conidiogenous cells and mature conidia that are brown to black and pyriform or lageniform (Su et al. 2016; Zhang et al. 2025 a, 2025 b). Phylogenetically, clades A, B, and C are placed in Sporidesmiaceae, clade D is accommodated in Xenosporidesmiaceae, whereas Lignosporidesmium represents an isolated lineage that cannot be assigned to any currently recognized family (Fig. 1). Therefore, based on a combination of distinctive morphological characters and phylogenetic evidence, we propose that the new genus Lignosporidesmium should accommodate L. tropicale, which forms a single, independent evolutionary lineage. The genus is herein placed in Diaporthomycetidae genera incertae sedis.