Flora of the canga of Serra dos Carajás, Pará, Brazil: Apocynaceae

Abstract This study presents a treatment of the species of Apocynaceae from the canga of the Serra dos Carajás, Pará. Detailed descriptions, keys for identification of genera and species, illustrations, data on geographic distribution, and morphological and ecological comments of the treated species are presented. Twenty two species and 13 genera were registered in the study area. The two species of Marsdenia and one of Matelea are particulary interesting. Marsdenia bergii and Matelea microphylla are endemic to the canga of Serra dos Carajás whereas Marsdenia thomasii is known only from two collections, one from Mato Grosso state and the other from the Carajás region.