Frullania cuencensis is newly reported from Texas, extending the documented range of this species north of Mexico to the United States. The species can be separated from F. riparia by its inflated, galeate lobules that have triangular proximal portions; subulate styli; and entire, somewhat recurved ventral leaf margins. Frullania mexicana is taken out of synonymy and confirmed from Arizona and New Mexico, as well as newly reported from Texas. It differs from both F. inflata and F. tetraptera in having differentiated marginal/median cells of the leaf lobe and an obovoid perianth with eight or more keels. Other distinctions between F. inflata and F. tetraptera are presented. Frullania mexicana has been confused and overlooked in the United States with several literature reports of F. inflata and F. pluricarinata specimens from Arizona and New Mexico belonging to F. mexicana.