The genus Cannabis has been treated taxonomically by several authors, but two main hypotheses predominate. Small and Cronquist (1976) concluded that the genus is monotypic and contains only Cannabis sativa L. Subspecies were named according to the economic purpose of the plants, i.e. fibre or drug, and varieties were assigned according to habitat (wild or cultivated). Schultes (1974) believed the genus is polytypic, with Cannabis sativa L. representing the fibre plants, C. indica Lam, the drug plants, and C. ruderalis Janis. the wild and weedy plants. A study of flavonoid variation was undertaken to determine which of the taxonomic schemes would be supported by this variation. Individual plants were examined by thin-layer chromatography and presence/absence data for nine flavonoids were analyzed by three types of computer programs. The infraspecific variation of flavonoids in the genus Cannabis supports the monotypic theory of Small and Cronquist (1976). No consistent, distinguishable groups were noticeable in the data. Wild taxa were more closely related to their cultivated progenitors than they were to each other. A division of the genus Cannabis into several species would not be supported by flavonoid variation. / Science, Faculty of / Botany, Department of / Graduate