Inselbergs as a paradise for new plant species: A new geophytic white-flowered Mandevilla (Apocynaceae) that inhabits the vertical walls of inselbergs in Southeastern Brazil

A new geophytic species of Mandevilla (Apocynaceae), found on vertical inselberg walls in Espírito Santo, Brazil, is described and illustrated. Distribution and habitat, etymological and taxonomic notes, as well as a preliminary conservation assessment according to IUCN guidelines are provided for the new species. Mandevilla unica resembles M. declinata and M. angustifolia , but differs from them by having inconspicuous interpetiolar colleters, longer petioles, and linear leaf blades. A key to the white-flowered species of Mandevilla from Espírito Santo illustrates the morphological similarities and differences among these species and the key features that distinguish the new species.