Boldoa, Gen. Sp. Pl.: 9. 1816 sec. Bittrich & Kühn (1993)
- Type: not designated
The genus is monotypic with B. purpurascens Cav. ex Lag. distributed from Mexico and the Antilles to northern South America. Along with Salpianthus and Cryptocarpus, Boldoa is placed within the tribe Boldoae (Douglas & Spellenberg 2010) and in several treatments (Standley 1911, 1918, 1931; Fay 1980; Pérez & al. 2000; Spellenberg 2001; Hernández-Ledesma & Flores 2003; González 2007) the genus has been included in the wide concept of the genus Salpianthus. Here we follow Bittrich & Kühn (1993) and Harling (2010) who consider them as separated genera, because of differences of the perianth: Boldoa has a campanulate perianth (2.0-3.5 mm long) with glandular and uncinated hairs, Salpianthus has a tubular perianth (6.0-7.0 mm long) with straight hairs, while Cryptocarpus has a pyriform perianth (1. 5-2. 0 mm). A revision and phylogenetic analysis including all the species of the tribe is necessary to evaluate the circumscription of the genera.