Taxonomic novelties in Helminthosphaeriaceae: morphological and phylogenetic evidence for Obovatispora gen. nov. and a new species from Polygonatum in Guizhou Province, China.

Obovatispora is established herein as a new genus to accommodate a novel hyphomycetous species, O. polygonati, collected from dead branches of Polygonatum in Guizhou Province, China. Phylogenetic analyses based on a concatenated LSU, ITS, and tef1-α dataset place Obovatispora within Helminthosphaeriaceae (Chaetosphaeriales, Sordariomycetidae). The genus is presently known only from its asexual morph and is characterized by macronematous, unbranched, septate, cylindrical conidiophores; mono- or polyblastic, cylindrical conidiogenous cells that occasionally bear lateral, bladder-like conidiogenous loci; and acropleurogenous, pyriform, obovoid to broadly ovoid conidia. This study provides detailed morphological descriptions, illustrations, and comparative assessments of the new taxon. The discovery of O. polygonati not only enriches the taxonomic framework of Helminthosphaeriaceae but also enhances understanding of species diversity and biogeographical associations linked to the medicinal plant genus Polygonatum.