Classification in Cannabis has been hotly debated among botanists for decades, but the most current thinking based on Hillig, and concurred by Clarke, places three species and seven sub-species in the genus. All drug marijuana varieties belong to a single species, C. Indica. All other non-drug varieties belong to either C. Sativa - European hemp, or C. Ruderalis - wild hemp.
Where it gets tricky is when the layman’s definitions of “sativa” and “indica” - generally based on leaf type - are used to make observations that this plant is a “sativa” due to its narrow leaves, versus the broad leaves of an “indica”. Clarke notes the existence of both broad leaf hemp varieties in China and the better known narrow leaf drug cannabis of southern India and South and Central America. Both refute the notion that leaf style is a primary characteristic of either species, C. Sativa or C. Indica.
That said, I still use the traditional leaf-type nomenclature in discussing drug cannabis varieties, as it is useful within that context. I also generally subscribe to the Linnaean concept that species classification is primarily defined by interfertility, which would suggest the traditional classification of a single Cannabis species with numerous sub-species.
-b420