Flora of the cangas of Serra dos Carajás, Pará, Brazil: Acanthaceae

Abstract Fourteen species belonging to three genera of Acanthaceae were found in the canga formations of Serra dos Carajás, Pará, Brazil. The genus Justicia is the most numerous, with nine species (five endemic to Serra dos Carajás), followed by Ruellia, with four species (one endemic to the state of Pará), and a single species of Mendoncia. Descriptions, identification keys, comments, geographic distribution, illustrations of the species and a new combination: Justicia divergens (Nees) A.S. Reis, A. Gil & C. Kameyama are presented.