Updating the occurrence of crassulacean acid metabolism (CAM) in the genus through carbon isotope analysis of species from Colombia.

is a widely distributed neotropical genus with 321 currently described species. This remarkable genus is the only one known to contain trees with CAM photosynthesis. To survey the occurrence of CAM in species from Colombia, we determined the leaf stable carbon isotope composition (δC) of 568 specimens from 114 species deposited in 12 Colombian herbaria. In the vast majority of specimens, δC values indicated that C photosynthesis was the principal contributor to carbon gain. δC values typical of strong CAM (less negative than -20‰) were observed in only five species, in four of them for the first time. All samples with CAM-type isotopic signatures were collected below 1,000 m a.s.l., whereas species with predominantly C occurred from sea level to 3,500 m a.s.l. Together with information already available in the literature, we conclude that CAM is present in 22% (35/156) of the species of investigated thus far.