The genus Mesochaete Lindb. is known from tropical to temperate regions of the east coast of mainland Australia and Lord Howe Island. It includes two species, M. undulata Lindb. and M. taxiforme (Hampe) Watts & Whitel. Leaf size, leaf cell dimensions and aspects of leaf cross-sectional anatomy appear to be the most reliable morphological features to distinguish the species and new information is given in support of their retention as separate species. Incorrect statements in the Flora of Australia and other Australian treatments are rectified. As there are no previous illustrations of the sporophyte of M. taxiforme, or descriptions of the peristome and spores of either taxon, complete illustrations of the two Mesochaete species are presented with a supplementary description of the sporophyte and, where available, SEMs of peristomes and spores. One of the taxa, M. taxiforme, is represented by very little fruiting material. Consequently, only one sporophyte was sacrificed for the SEM work. Morphologically, peristomes and spores of both taxa appear almost identical.