Allamanda calcicola (Apocynaceae), an overlooked new species from limestone outcrops in the States of Minas Gerais and Bahia, Brazil

Allamanda calcicola Souza-Silva & Rapini, an overlooked new species endemic to the limestone outcrops along the Sao Francisco River Basin, in south-western Bahia and northern Minas Gerais, Brazil, is described and illustrated. It was confused with A. martii and A. schottii, two species from eastern Brazil, which (along with A. polyantha) form a different complex of closely related species. However, A. calcicola is more closely related to A. puberula, another species from the semi-arid region of Brazil.