RESUMEN

Frullania (subg. Trachycolea) sect. Trachycolea has been studied using integrative taxonomy methods and utilizing sampling from almost all areas of distribution of the species previously referred to this section. A phylogenetic analysis based on nuclear ribosomal ITS1-2 and chloroplast trnL-F sequence data and a morphological study reveal a wide range of morphological variability within specimens that has largely disguised the overall taxonomic diversity. Frullania parvistipula, previously regarded as a widespread species, has been found to represent a group of separate species within different sections of F. subg. Trachycolea: F. caucasica and F. conistipula in F. sect. Trachycolea, F. parvistipula in F. sect. Australes, and F. fukuzawana in F. sect. Integristipulae II. Illustrations of the type specimens of F. conistipula, F. fukuzawana, and F. parvistipula, as well as illustrations of the sequenced specimens belonging to two of the discussed species (F. conistipula and F. parvistipula), are provided. The morphological differences separating the highly similar F. caucasica, F. conistipula, F. fukuzawana, F. koponenii, and F. parvistipula are discussed. A dichotomous key is presented for accepted species. New combinations are provided for two taxa.