Observations on the genus Exobasidiellum

Abstract

The type specimens of Exobasidiellum graminicola (Bres.) Donk and E. culmigenum Webster & Reid were examined. The basidia of E. graminicola are elongate and taper basally as in other Exobasidiaceae; as in some species of Exobasidium, the basidiospores become transversely septate and produce small conidia during germination. The basidia of Exobasidiellum culmigenum develop in two distinct phases: (1) a probasidium is formed and within this karyogamy occurs; (2) a metabasidium develops from the probasidium and the diploid nucleus migrates into the apex of this structure before undergoing meiosis. The basidiospores of E. culmigenum germinate by germ tube. On the basis of these and other features, E. culmigenum is transferred to Galzinia as G. cubnigena (Webster & Reid) Johri & Bandoni comb. nov.