Generic additions to the Rapateaceae of Rondônia, Brazil

ABSTRACT Rapateaceae is a monocot family centered in the Guiana Shield region of South America. This article reports four generic additions to the Rapateaceae of Rondônia, a state in northern Brazil. Cephalostemon gracilis (Poepp. & Endl.) R.H.Schomb., Duckea cyperaceoidea (Ducke) Maguire, Monotrema xyridoides Gleason, and Schoenocephalium cucullatum Maguire were recorded in lowland savannas and open white-sand ecosystems in the state. These findings extend significantly the known diversity of the Rapateaceae taxa occurring in Rondônia, and represent an extension of their geographical distribution to a Brazilian state with no part of its territory in the Guiana Shield.