Vascular flora of an inselberg in the state of Paraiba, mesoregion of backcountry, Northeast of Brazil

Abstract

Inselbergs, or mountainous islands, are rocky elevations generally monolithic, geologically formed by granites. These formations have peculiar ecological conditions and are excellent sources of ecological studies and floristic diversity. This study aimed to identify the vascular flora of an Inselberg in the Patos municipality, state of Paraíba, Northeast of Brazil, and list the altitudinal gradients of the species in the study area. The study was developed in Inselberg Espinho Branco, between the months April 2012 to July 2013. Botanical collections were made monthly, following the usual methodology in taxonomy, being the Inselberg divided into three altitudinal gradients: base (250-305 m), middle portion (305.1-360 m) and top (360.1-415 m). The identifications were performed mainly by morphological analysis of specimens with the aid of stereoscopic-microscope. The flora of the study area is represented by 101 species belonging to 84 genera and 45 families. The six most representative families in number of species were: Fabaceae (12 spp.), Euphorbiaceae (11 spp.), Malvaceae (seven spp.), Convolvulaceae (six spp.), Asteraceae and Poaceae (four spp. each). The herbaceous habit was predominant. Nine species are endemic to the Caatinga and six are new records for the state of Paraiba. The majority of this species was collected at the base of Inselberg.