A synopsis of Byttnerieae (Malvaceae, Byttnerioideae) from the Atlantic Forest, with notes on geographical distribution, nomenclature, and conservation

ABSTRACT This synopsis presents diagnostic characters and comments on morphological variability, distribution, and conservation of species of Byttnerieae (Malvaceae, Byttnerioideae) from the Atlantic Forest. Byttnerieae is represented by species from two allied genera in this phytogeographic domain: Ayenia L. and Byttneria Loefl. An extensive literature survey along with herbarium collection analyses revealed the occurrence of 20 species in the Atlantic Forest, nine of which are endemic to Brazil. Seven species are restricted to the Southern portion of the Atlantic Forest, i.e., occurring from southern São Paulo state to the state of Santa Catarina, with most records being in Brazil, but some species also occur in Argentina and Paraguay. Beyond the Southern portion of the Atlantic Forest, three species are restricted either to the state of Rio de Janeiro or to Bahia, in Brazil. An identification key focusing on vegetative characters, as well as illustrations and notes on species distribution and conservation, are presented. Nomenclatural comments or updates for some taxa were provided, including: the designation of lectotypes for six names; the amendment of authorship of one name (B. gracilipes); and reassessment of the distribution of A. glabrescens, an endemic species of dry deciduous forests of Bahia whose precise location was unknown.