Cannabaceae is a family of flowering plants that includes about 170 species in 11 genera, including hops, hackberries and cannabis. The cannabis genus includes three species: Cannabis sativa, Cannabis indica and Cannabis ruderalis. All three species contain more than 100 cannabinoids, including tetrahydrocannabinol (THC) and cannabidiol (CBD).
Cannabis sativa plants are tall and loosely branched, whereas Cannabis indica plants are shorter, conical and have thick, dense branches. Cannabis ruderalis is the runt, rarely growing over 2 feet tall with thin stems and little branching. Ruderalis has low THC concentrations but larger amounts of CBD and, while mostly excluded in modern Western cannabis cultivation, has been used for centuries in Russian folk medicine. Hybrids are cross-species of indicas and sativas.
While the psychoactive effects do not cleanly cleave, the highs of indica plants are generally more relaxing, while a sativa high tends to be more energetic.