A unique feature of Calatola is the presence in all parts of the plant of a compund, identified as a flavonoid in the present study, that oxidizes to a blue-violet color upon exposure to air. The present revision, which incorporates data from traditional morphology, field characters, chromosome numbers, pollen, germination and seedling morphology, recognizes five species for Mexico, adding C. costaricensis Standl. C. laevigata is shown to be a rare species of the Pacific slope, while populations of the Mexican Gulf slope, Guatemala, and Belice previously referred to this taxon represent an undescribed species. C. costaricensis displays geographic variation and possible intergradation with C. mollis and thus requires further study.
Seed germination occurs in ca.
All species in Mexico are represented by either small or very dispersed populations and are thus of conservation concern.