A revision has been made of the hepatic genus Brachiolejeunea (Spruce) Schiffn. (family Lejeuneaceae, subfamily Ptychanthoideae). Within this genus two subgenera were recognised: subg. Brachiolejeunea and subg. Plicolejeunea Schust. (n order to distinguish taxonomic entities within these subgenera and to evaluate their affinities, the morphology and anatomy of the gametophyte and the sporophyte have been studied. Data on cytology and sporeling development, obtained from living and cultured specimens, were added. Sporophyte characters have been studied with light microscopy (LM) and scanning electron microscopy (SEM). Besides a considerable reduction in the number of accepted species, the main result of this study is that the traditional delimitation of Brachiolejeunea cannot be maintained. The two subgenera appear to be different in many characters, several of them new, and are accordingly elevated to generic level. The genus Brachiolejeunea (4 species) now comprises only the former subgenus of that name; the generic name Frullanoides Raddi is reinstated for the subg. Plicolejeunea (7 species and 1 subspecies). For both genera the morphology and anatomy are described, the previously neglected sporophyte generation being treated in particular detail. In each of the genera a different type of sporophyte is present; a “fenestrate-type” in Frullanoides, a “nodular-type” in Brachiolejeunea. From a of the distribution patterns it appears that both genera probably originated in the western part of Gondwanaland. Brachiolejeunea is confined to that area and may presently be characterized as a Neotropical-montane element. One species of Frullanoides is pantropical, the others are neotropical. The species of Brachiolejeunea are predominantly epiphytes of mountain forests and have a rather narrow drought tolerance; the species of Frullanoides generally occur in a greater variety of habitats and have a wider drought tolerance. A consideration of generic relationships shows that the affinities of genera are very different. For both genera identification keys are provided, each species and subspecies is illustrated and for each taxon the following information is provided: synonymy with relevant literature and typification, a description, geographical distribution with distribution map, and notes on ecology, differentiation and variation. The second part of this study contains a short review of the genus Blepharolejeunea S. Arnell, which has been emended to accommodate several diverging species of Brachiolejeunea and Dicranolejeunea. Blepharolejeunea is related to both genera and is characterized as a Neotropical-montane element. In the third part of this study the sporophyte generation in the subfam. Ptychanthoideae is analysed with Scanning Electron Microscopy. Fenestratetype and nodular-type sporophytes are described and the different affinities of these types are discussed. The new tribe Brachiolejeuneae van Slageren & Berendsen is created to accommodate the genera of Ptychanthoideae with nodular-type sporophytes.