hydroponics because this pH range is hostile to most bacteria and fungi. Tissue culture multiplication has become important in producing medically important clones, while seed production remains the generally preferred means of multiplication. Sativa plants have narrow leaves and grow best in warm environments. They do, however, take longer to flower than their Indica counterparts, and they grow taller than the Indica cannabis strains as well. Cultivars Broadly, there are three main cultivar groups of cannabis that are cultivated today: Cultivars primarily cultivated for their fibre, characterized by long stems and little branching. Cultivars grown for seed which can be eaten entirely raw or from which hemp oil is extracted. Cultivars grown for medicinal or recreational purposes, characterized by extensive branching to maximize the number of flowers. A nominal if not legal distinction is often made between industrial hemp, with concentrations of psychoactive compounds far too low to be useful for that purpose, and marijuana. See also Cannabis indica Cannabis ruderalis Cannabis strains Difference between C. indica and C. sativa References External links Cannabis strains Crops originating from Asia Entheogens Euphoriants Flora of Central Asia Hemp Medicinal plants of Asia Phytoremediation plants Plants described in 1753 Plants used in traditional Chinese medicine Taxa named by Carl Linnaeus