Pisonia, Sp. Pl. 1: 1026. 1753 sec. Bittrich & Kühn (1993)
- Type: Pisonia aculeata
- =Rockia in Oesterr. Bot. Z. 63: 289. 1913 syn. sec. Bittrich & Kühn (1993)
- Type: Rockia sandwicensis
The genus includes shrubs, trees and woody climbers characterised by stout spines on the stems and coriaceous fruits with stipitate glands. Its distribution is pantropical with a center of diversity in the Neotropics. Molecular phylogenetic studies (i.e. Douglas & Manos 2007; León de la Luz & Levin 2012) support the monophyly of Pisonia, although the genus was poorly sampled in both studies. Pisonia has not been monographed and the number of species is uncertain; some treatments considered 40 species (e.g. Spellenberg 2001; DeFilipps & Maina, 2003; González 2007) whereas others (e.g. Spellenberg 2003) considered a range between 10-50 species; in the literature there are a lot of accepted and unresolved names.