Untersuchungen über die Gattung Discostroma Clements(Ascomycetes)

Abstract

The systematical relations within a group of genera of Amphisphaeriaceae are shown by using the apical structure of the ascus and conidial forms as criteria. The genus Discostroma with the genera Seimatosporium and Sporocadus, which occur as its conidial states, was examined more intensely. In all eight species with Rosa, Ribes, Gornus and Epilobium hosts are involved. The identity of these species with already known species of the Fungi Imperfecti is shown using cultural experiments. An exception is D. saccardoana, for which only the perfect state was found in nature. Four new species are described: D. sanguineae on Cornus species and D. polymorpha, D. canina, and D. rosae on Rosa species. Of Seimatosporium hysterioides only the imperfect state is described, whereas the perfect state is not known. The occurence of filamentous appendages as suitable systematic criterium was examined. It is shown that the genus Sporocadus is well defined by the absence of appendages, whereas in Seimatosporium species the number of appendages varies considerably.