Dioscorea L. has an estimated 450 species, of which more than half occur in the Neotropics. As many as 57 species are represented in Colombia: of these, 13 are endemic and 4 are introduced. Among the native species, 15 were last collected in Colombia between 60 and 165 years ago; 16 species were described after the publication of the last comprehensive treatment of the genus (Knuth, 1924) and their affinities remain unknown and/or untested. The native species include Dioscorea trifida L.f., the only domesticated American food yam. In Colombia, this species is widely cultivated as a subsistence crop in lowland areas and has a long tradition of use among Amazonian indigenous peoples. Dioscorea includes many other economically important species (actual and potential) but taxonomic problems abound in the genus, and the Colombian species have never been revised. A major goal of international Dioscorea research is to produce a robust infra-generic classification that is supported by phylogenetic data. Some progress has been made, but data deficiencies remain particularly acute among the Neotropical species. The present study aims to address these deficiencies by: 1) monographing the Colombian species of Dioscorea, 2) using the Colombian taxa to build on an existing chloroplast DNA dataset, and increase the Neotropical sampling in the global phylogeny, 3) estimate the genetic diversity of Dioscorea in Colombia, 4) reveal the affinities of poorly known taxa and evaluate their relationships to economically important species and 4) assess the relationships between Neotropical and Paleotropical species in the context of prevalent biogeographic hypotheses. An additional goal of the proposed research is to collect ethnobotanical data about Colombian Dioscorea in the field and in public markets around the country with a special focus on the use, management and cultural significance of Dioscorea trifida in the Colombian Amazon. Finally we hope to rediscover the 15 "lost" species, not collected in Colombia for more than six decades.