A new genus, Elliptolagenoidisporium, is proposed herein to accommodate a novel hyphomycetous fungus, E. paris, isolated from dead branches of the medicinal plant Paris sp. from Guizhou Province, China. Phylogenetic analyses based on a combined dataset of LSU and ITS sequences robustly support the placement of Elliptolagenoidisporium within the family Lachnaceae (Helotiales). Comprehensive morphological descriptions, illustrations, taxonomic notes, and phylogenetic evidence are provided to substantiate the establishment and systematic position of this new genus and species. Currently, Elliptolagenoidisporium is known only from its asexual morph, which is characterized by micronematous, mononematous, solitary, erect, simple or branched, septate, straight or flexuous, cylindrical conidiophores; holoblastic, integrated, terminal, cylindrical to lageniform conidiogenous cells; and acrogenous, solitary, septate, acerose, fusiform, lageniform to ellipsoidal, verrucose, guttulate, smooth or echinulate conidia. The discovery of E. paris provides valuable insights into the species diversity, ecological functions, and biogeographical distribution of saprobic fungi associated with medicinal plants in karst ecosystems.