Leptotheca is recognized as comprising two species,L. boliviana Herzog (L. costaricensis Cardot & Thér., syn. nov.) andL. gaudichaudii Schwaegr. The latter species consists of two varieties, var.gaudichaudii and var.wattsii (Cardot) comb. nov. The genus is characterized by its acrocarpous habit, lanceolate leaves with an excurrent costa and smooth, thick-walled cells, and the occurrence of uniseriate, usually papillose propagula on the upper stems. The genus is transferred from the aulacomniaceae to the Rhizogoniaceae on the basis of gametophytic and sporophytic characters. A key to the genera of the Rhizogoniaceae is provided.