Studies in Mycology No. 8

The genus Thielavia is restricted to Pyrenomycetes characterized by non-ostiolate ascomata with a wall of textura epidermoidea and ascospores with a single distinct germ pore; 18 species are recognized. The genus Chaetomidium is maintained for 6 species having ascomata with a pseudo-parenchymatous wall, covered with characteristic hairs, and limoniform ascospores with a single germ pore. The new genus Melanocarpus is introduced for Myriococcum albomyces Cooney & Emerson, a thermophilic fungus with dark, usually smooth, pseudoparenchymatous ascomata, and ovoid-oblate ascospores with a single distinct germ pore. Four species characterized by ascospores with two germ pores, one at each end, and by the formation of a Chrysosporium conidial state are classified in the genus Corynascus. A fungus with light ascomata covered with dark hyphae and having ellipsoidal ascospores with two prominent germ pores is described as type of tbe new genus Corynascella. Two further new species are described in the genera Thielavia and Apodus. Species with one-celled ascospores with a germ slit are classified in the genera Coniochaetidium and Ephemeroascus. Identification keys and descriptions of the genera are given.