Rubroshiraia gen. nov., a second hypocrellin-producing genus in Shiraiaceae (Pleosporales).

Shiraiaceae is an important family in Pleosporales (Dothideomycetes), which includes medical fungi and plant pathogens. Two hypocrellin-producing taxa, and a novel genus , typified by are treated in this article. Maximum likelihood analysis, generated via RAxML (GTR+G model), using a combined SSU, LSU, TEF1 and RPB2 sequence dataset, shows that is close to and belongs to the family Shiraiaceae. Descriptions, illustrations and a taxonomic key are provided for the genera in Shiraiaceae. morphologically differs from in having small and dark ascostromata and filiform ascospores. Production of the ascostromatal metabolites, hypocrellin A and B, were examined by HPLC and spectrophotometer. The content of hypocrellin A and B of specimen HKAS 102255 ( ) is twice that produced by HKAS 102253 ( ). To clarify the relationship between and , type material of the latter was examined and provided the illustration.