The classification of the speciose leafy liverwort genus Plagiochila into species and sections is still in a preliminary state. Based on phylogenetic analyses of a dataset comprising nuclear ITS and chloroplast rps4 and rbcL sequences, we reject an earlier proposed synonymy of the Asian-Australasian Plagiochila sect. Abietinae and the pantropical P. sect. Vagae. A monophyletic sect. Abietinae is recognised, containing a clade with five accessions of P. abietina sister to a single accession of P. hampeana. This Abietinae clade nests in a larger Plagiochila clade which also retrieves monophyletic sects. Fruticosae, Trabeculatae, Peculiares, Plagiochila and Poeltiae. Plagiochila sect. Vagae is placed sister to P. sect. Africanae. Two P. abietina accessions from Australia form a sister relationship with a clade comprising three P. abietina accessions from the Fiji Islands. Based on the example of P. patula, we discuss the benefits of including type or topotype specimens in revisionary studies considering molecular and morphological evidence.