Cuphea (Lythraceae) in the state of Rio Grande do Sul, Brazil

Abstract The present work aims to provide a discussed floristic treatment for Cuphea (Lythraceae) from the Rio Grande do Sul state, Brazil. Morphological, ecological and geographic distribution data were obtained through the revision of several herbaria and from collection expeditions. A morphological analysis of the seeds under scanning electron microscopy and a preliminary assessment of the conservation status of the species were included. As a result, 12 native species and one variety were recorded for Rio Grande do Sul, often found in wet to dry grasslands of the Pampa biome. Cuphea campylocentra, C. linifolia and C. lysimachioides were preliminarily classified as threatened according to the categories and criteria of IUCN, joining C. confertiflora, which was officially cited in the List of threatened flora in Rio Grande do Sul. This study provides an identification key, illustrations, maps, morphological descriptions, and comments on the ecology, taxonomy, and geographic distribution of the Cuphea species in Rio Grande do Sul state.