Classicula: the teleomorph of Naiadella fluitans.

A new genus, Classicula, and a new species, Classicula fluitans, are described in the Urediniomycetes for the teleomorph of Naiadella fluitans. Classicula fluitans forms transversely septate basidia with subapically swollen sterigmata and long fusiform basidiospores. An integrated analysis of morphological, ultrastructural and molecular data indicates that Classicula fluitans is a member of the Urediniomycetes. Among the Urediniomycetes, Classicula fluitans shares the formation of simple septal pores associated with microbodies and tremelloid haustorial cells only with the hyphomycete Jaculispora submersa. In addition, in our molecular phylogenetic analyses with at least two representatives of all known urediniomycetous groups, Classicula fluitans appears together with Jaculispora submersa in a statistically well-supported cluster. Accordingly, the family Classiculaceae and the order Classiculales are proposed to accommodate these fungi in the Urediniomycetes.