The genus Dahlia comprises 37 species and is restricted to the highlands of Mexico. It ranks among the most important ornamental plants with more than 1000 varieties. As part of a project for the collection and conservation of genetic resources in the genus Dahlia, wild plant collections were conducted in cooperation with the Universidad Nacional Autónoma de México (UNAM) from 1999 to 2002. 23 of these species are in cultivation in the Hamburg Botanical Garden.