Exploring Sisyrinchium (Iridaceae) diversity in the Atlantic Forest Biome: three new species in S. sect. Viperella

The Southern and Southeastern regions of Brazil present the highest species richness of Sisyrinchium, and the taxa are mainly distributed in the Atlantic Forest Biome. Here, three new species belonging to Sisyrinchium sect. Viperella from this biome are described: S. caratuvense is endemic to the high altitude grasslands of eastern Parana, S. usneoides is endemic to the campo rupestre phytophysiognomy in southern Minas Gerais, and S. iguazuanum has a wider distribution, occurring in the grasslands of western Santa Catarina and Parana (Brazil), and eastern Misiones (Argentina). Descriptions, illustrations, comparisons to related taxa and conservation status are provided.