Ruehssia quirinopolensis (Apocynaceae), a new species from the Cerrado Domain, Brazil

Abstract A new species of Apocynaceae, Ruehssia quirinopolensis, endemic to Serra da Confusao do Rio Preto and Serra da Igrejinha, Quirinopolis, state of Goias, Brazil, is described and illustrated. It resembles R. rupestris, differing by the white corolla, adaxially villose and with a longer tube, and by its corona lobes with the upper portion lanceolate. Besides a distribution map for the new species, we provide a key to identify the nine species of Ruehssia that occur in Goias. Ruehssia quirinopolensis is assessed here as Critically Endangered (CR).