The genus Plethadenia is revised. It consists of two species, which are distributed in the Greater Antilles and are likely endangered, viz. P. cubensis from E Cuba and P. granulata from N Haiti and the SW Dominican Republic. The species differ in the indument, the morphology of the sepals and disc, and in the size of the flowers and follicles. The genus and its species are described, and distributional data, a distribution map, illustrations and a key to the species are provided. The systematic position of Plethadenia within the Rutoideae sensu Engler is briefly discussed.
Willdenowia is an international peer-reviewed journal publishing original research papers in English from the entire fields of plant, algal and fungal systematics, covering the evolution, taxonomy and nomenclature of these organisms as well as related fields such as floristics and plant geography. Three issues appear each year (in April, August and December) in an open-access online edition and a print edition. Individual papers may be published in the online edition as fast-track articles ahead of inclusion in these issues.