Studies in the Genus Sporonema

The writer's interest in the genus Sporonema followed the repeated interception of a fungus described as Excipula diapensiae Rostr. In studying the possibility of placing this species in Sporonema, the heterogeneous nature of the sjpecies heretofore assigned to the genus became apparent. The writer believes that the following account will be of interest to others. Heterogeneity in the genus has been noted before. It is in part due to von Hoehnel's (5) criticism of certain species that Diedicke (3, p. 743) included only 5. phacidioides and S. catalpae in Sporonema. Descriptions of at least twenty-nine species appear in the literature. A number of them have been transferred to other genera, but nineteen species remain in the form genus Sporonema. Species of Sporonema, like other Discellaceae, are distinguished by pycnidia which open by a split or lacination of the wall, and a cupulate or disc form at maturity. These characters are often poorly developed and some species are not easily distinguished from certain species in genera of other families. The shape of the pycnidia may be nearly spherical at first, but it is usually depressed or lenticular at maturity before opening. After opening the cupulate or disc-like character is evident.