Geographic review on the specimens of the Caatinga Biome in the Jardim Botânico do Rio de Janeiro (RB) herbarium.

Background: This article provides a quantitative description of flora specimens stored in the Jardim Botânico of Rio de Janeiro Herbarium that belongs to the Federal Conservation Units of Caatinga's phytogeography domain. The Caatinga represents 11% of Brazilian territory and is, in South America, the largest and most biodiverse semi-arid tropical ecoregion, yet only 5% of its territory is covered by Federal Conservation Units, with few collections of flora samples. Thus, providing a georeferenced inventory of existing collections is essential for purposes of species distribution, environmental management and conservation.