The taxonomic study of Cactaceae in Serra Negra, Minas Gerais is presented. The family is represented in the area by five genera and nine species: Arthrocereus melanurus subsp. magnus, Hatiora salicornioides, Lepismium houlletianum, Opuntia monacantha, Rhipsalis elliptica, R. floccosa subsp. pulvinigera, R. juengeri, R. lindbergiana and R. pilocarpa. The first and last species are considered threatened for the State of Minas Gerais. It must be highlighted that Arthrocereus melanurus subsp. magnus was known previously only from the Parque Estadual do Ibitipoca and the present data resulted on an expansion of its known distribution area. Conservation of not yet protected areas like Serra Negra is very important, because their unique assemblage of species is constantly damaged by frequent and disorganized tourism and illegal plant collection. Local forest and natural fields are being further degraded as they are transformed into pasture land, and the threats faced by many species continue to grow. Identification keys, descriptions, illustrations, taxonomic and ecologic comments are provided for the species treated.
conservation; Atlantic Forest; floristics; Mantiqueira Range; taxonomy
