Taxonomic synopsis of Caesalpinioideae (Leguminosae) in the national forest of Caxiuanã, Pará, Brazil

Abstract The National Forest (Flona) of Caxiuanã is located in the state of Pará, in northen of Brazil and spanning the municipalities of Portel and Melgaço. It inserted in the phytogeographic domain of Amazon, the FLONA encompasses vegetation types including Terra firme forest, Várzea, Igapó, Campinarana, and Capoeira. The objective of the study is a synopsis of Caesalpinioideae species (except the genus Inga) that occur in the Flona of Caxiuanã. Fieldwork and the herbarium consult of MG, IAN and RB were undertaken between August 2014 and July 2015. This paper treats 21 genera, among 22 that occur in Flona of Caxiuanã. Distribution analysis of the species of Caesalpinioideae reveals that 77% are restricted to the Amazonia biogeographic domain and 2,8% are endemic to Brazilian Amazonia. The genera represented by most species are Parkia (seven spp.), Abarema (three spp.), and Zygia (three spp). The majority of species are reported from Terra Firme forest (79%). The treatment includes an identification key to the species, illustrations, diagnoses and comments on the species.