Rhagadolobiopsis, a new genus of Parmulariaceae from Brazil with a description of the ontogeny of its ascomata.

During a survey of the mycobiota of selected Brazilian ferns we discovered a new genus of Parmulariaceae causing tar spot-like symptoms on leaves of Thelypteris serrata (Thelypteridaceae). The new genus and species, decribed as Rhagadolobiopsis thelypteridis, differs from morphologically similar species of Rhagadolobium in possessing colorless, aseptate ascospores and a hymenial gel that does not become blue with iodine. In addition this is the first record of a fungus on T. serrata, and the first Parmulariaceae recorded on a member of the Thelypteridaceae. The ontogeny of the ascomata is described and illustrated here for the first time for the Parmulariaceae.