Morphological information was analyzed to evaluate whether Pithecellobium insigne, usually considered a synonym of Pithecellobium lanceolatum, is a different species. This question was addressed by a multivariate statistical analysis: cluster analysis, principal component analysis, and discriminant analysis using data obtained from herbarium specimens collected in Mexico, Central America, and northern South America. The results support P. insigne as a distinct species from P. lanceolatum. Significant differences with P. lanceolatum are: length of the floral bracts, length of the staminal tube, and thickness of the fruit. Pithecellobium insigne has the largest dimensions for all these features. Hybridization is possible and apparently takes place between both species in the Isthmus of Tehuantepec (Mexico), where populations of both species are parapatric and few specimens with intermediate characters were observed. A key to differentiate both taxa, as well as information about morphology, common names, ecology, conservation, and phenology of P. insigne is also included.