Two little-known species of Meconopsis (Papaveraceae), M. lepida and M. psilonomma, first collected by Reginald Farrer on Gansu Min Shan, China, in 1914, were recently rediscovered and are here revised based on literature studies, field research and an examination of specimens. Accounts of the rediscoveries and detailed revisions are accompanied by explanatory photos, maps and tables. Two new varieties of M. psilonomma, var. zhaganaensis and var. calcicola, are described.