Dioscoreales are a small but systematically and economically significant order of monocotyledons. The most diverse and important member is the yam genus, Dioscorea L., a source of dietary starch at macroeconomic to rural community levels. Other species of Dioscorea provided the chemical basis of corticosteroid drugs and oral contraceptives. Ally families comprise the unusual, largely achlorophyllous (heteromycotrophic) Burmanniaceae and the relatively unspecialised Nartheciaceae. The World Checklist of Dioscoreales lists all validly published names of yams and their allies, providing the source of their publication and indication of which names are currently accepted and which are synonyms, making it a standard nomenclatural reference for further research into this important family. The World Checklist of Dioscoreales: . Lists all names ever published . Lists all accepted species with their geographical distribution . Indicates full synonymy . Provides a single source guide to the correct names of all yams and their allies . Provides an invaluable reference for applied yam researchers,e.g. pathologists, geneticists, plant breeders, conservationists, foresters, ethnobotanists, ethnoarchaeologists and anthropologists