Abstract
A new species of Xyris from the Southern and Southeastern regions of Brazil is described herewith. Xyris cervii belongs to Xyris section Nematopus, which is characterized by having basal to central placentation. Xyris cervii is morphologically similar to X. tortula, but differs by its deliquescent sheath with long hairs at the margin sheath, in addition to lanceolate and sub-equilateral, lateral sepals. A description, illustrations, geographic distribution and taxonomic comments are also provided.