Cannabis is one of the first plants cultivated by humans. I think classification is simplified by using 4 species. Cannabis ruderalis, C. indica, C. sativa and C. hemp. C. ruderalis has origins in central Asia. Usually less than 2 ft tall, spindly, auto-flowering, maybe 1% THC and CBD. It could be the ancestor of the other species. Natural and human selection created land races adapted to different latitudes and climates. C. indica, usually less than 4 ft tall, conical, dense foliage, compact buds, high THC, about 1% CBDs. C. indica ‘afghanica Clarke’ evolved for a long time at about 35 deg N, in a dry climate, slightly acid to slightly basic soils, often calcareous. C. sativa, usually more than 4 ft tall, open branch and foliage structure, loose buds, high THC, about 1% CBDs. Adapted to sub-tropical latitudes, wetter climate, somewhat acid soils with lower nutrient concentration. More resistance to mould is a recessive trait. C. hemp, usually very tall, little branching, loose buds, high CBD, about 1% THC. Many land races adapted to different climates and latitudes. The chemical pathway for THC and CBD is either / or. The minor constituent is there because it’s chemical pathway is active at a very reduced rate. New varieties/hybrids, almost anything is possible and the industry is a mess. A variety like ‘purple Kush’ from different seed companies or growers might be similar, but they usually have different chemistry and genetics. More on how this relates to growing, soon.