New species of the genus Epistephium (Orchidaceae, Vanilloideae)

The morphological study of the herbarium material representing Epistephium (Orchidaceae, Vanilloideae) led to the discovery of two groups of specimens that significantly differ from all known species of the genus. The results of literature data study and of comparative analysis of those and other specimens suggest that these collections represent new taxa that we describe as E. garayi and E. kubiyuense. The distinguishing features of the species are indicated. As both new species are reported from Colombia (E. garayi, also from Guyana), the key for the determination of all Colombian representatives of the genus is included. Information on the ecology and distribution of newly described taxa is presented.