Chlorostroma subcubisporum gen. et sp. nov. and notes on the systematic position of Thuemenella cubispora

Chlorostroma subcubisporum is a new genus and species erected to accommodate a taxon featuring a green stroma bearing perithecia, asci with an apex that does not become blue in iodine, and subcubical brown ascospores with a prominent germination slit. The two extant collections are inhabitants of Hypoxylon stromata from North Carolina. Although this taxon seems to be a member of family Xylariaceae (Xylariales, Ascomycota), its position is equivocal owing to anomalies in cultures and molecular data. Thuemenella cubispora, which C. subcubisporum resembles in general ascus and ascospore morphology, was tentatively considered by others to be a member of family Xylariaceae primarily on the basis of its Nodulisporium - like anamorph. Molecular data presented herein supports this taxonomic disposition.