The fine structure of hyphal septa in the Tremellaceae has shown a number of modifications of the characteristic dolipore–parenthesome type septum. These variations appear of phylogenetic importance and systems of classification have been proposed based upon septal pore structure of a limited number of species. This study reports the fine structure of additional tremellaceous genera,Basidiodendron, Exidiopsis, Sebacina, andTremellodendron. All species examined have dome-shaped pore caps bounded by unit membrane and with an electron-dense lamella in the pore cap lumen. Pore caps appeared nonperforate inTremellodendronandBasidiodendron, while narrow discontinuations or distinct perforations were found inExidiopsisandSebacina. Thus, their pore cap architecture is similar to that ofExidiaand other heterobasidiomycetes with the exception of species ofTremellaand members of the Filobasidiaceae. It is suggested that schemes of classification based upon the fine structure of a limited number of taxa may be premature.