A synopsis of the genus Disperis Sw. (Orchidaceae)

An infrageneric classification is provided for the genus Disperis Sw. (Orchidaceae, Orchidoideae, Diseae), with a complete enumeration of all species. The genus comprises 74 species of deciduous herbs that grow largely terrestrially in forest, scrub and grassland. Two subgenera are recognised in this study. Subgenus Dryorkis comprises 44 species found largely in the tropics and subtropics of Africa, Madagascar and Asia and is defined by a deeply bilobed lip appendage and possibly by apomorphic, baculate pollen. In addition, in many species the lateral sepals are basally fused and the rostellum arms are simple and not twisted. Subgenus Disperis comprises 30 species mainly in southern Africa and is defined by an entire lip appendage and usually twisted rostellum arms.Within these subgenera some well defined groups of morphologically similar and presumably related species can be distinguished but the existence of several unusual species makes it premature to propose them as formal taxa. They are consequently recognised as “informal groups”. Subgenus Disperis appears to be a monophyletic group but the phylogenetic status of subgenus Dryorkis is not clear at present. The taxonomic value of several vegetative and floral structures is briefly discussed.