Due to the overwhelming lack of modern taxon studies in the Marchantiophyta, relatively few species have been typified. As a result, it is not uncommon to find that the current interpretation of a species is not compatible with the actual type specimen. This is the problem that we encountered with Fossombronia angulosa, the type of which proved to be F. pusilla. The only solution, in this case, that will preserve current usage of F. angulosa is to propose conservation. A second kind of problem was encountered with type collections that contained two or more species of Fossombronia. In several instances, such mixed collections were compounded by the issue of exsiccatae sets. These problems have been found associated with several European and North American species. In this scenario, careful selection among the duplicates is most critical to maintain contemporary application of each name. Type specimen designations, such as those we have effected with all taxa in the genus Fossombronia, are essential not only to circumscribe correctly each taxon, but also to insure stable nomenclature for the future.

Key words: liverworts, nomenclature