Abstract
Helminthosporium is a polyphyletic genus in Massarinaceae (Pleosporales). Species of Helminthosporium are characterized by having septate and erect conidiophores, acro-pleurogenous and distoseptate conidia with a ring-shaped scar at the base. During a survey of fungal diversity in Sichuan Province, China, six Helminthosporium-like isolates were collected from dead branches of unknown trees. Five barcodes, including ITS (ITS1-5.8S-ITS2), SSU, LSU, TEF1, and RPB2 were amplified and sequenced. Morphological examination and multi-locus phylogenetic analyses revealed two new Helminthosporium species (H. chengduense sp. nov., and H. chinense sp. nov.), a new genus (Synhelminthosporium gen. nov.) with a type species Synhelminthosporium synnematoferum sp. nov., and two known species (Helminthosporium submersum and H. velutinum) within Massarinaceae. The new genus Synhelminthosporium differs from the phylogenetically closest genus Helminthosporium by producing synnematous conidiophores. This work expands our understanding of the diversity of Helminthosporium-like taxa in Sichuan Province, China.