Tiny samples of Cannabis plants also can be identified with precision by microscopic examination of leaf cells and similar features, but that requires special expertise and equipment. sativa proved too unwieldy, and never gained many adherents. and American taxonomist Arthur Cronquist published a taxonomic revision that recognizes a single species of Cannabis with two subspecies: C. Sativa is the most widespread variety, which is usually tall, laxly branched, and found in warm lowland regions.
It is also known as hemp, although this term is often used to refer only to varieties of Cannabis cultivated for non-drug use. ruderalis), which is commonly described as "auto-flowering" and may be day-neutral. In the 1970s, the taxonomic classification of Cannabis took on added significance in North America. Indica designates shorter, bushier plants adapted to cooler climates and highland environments.
To satisfy the UN Narcotics Convention, some cannabis strains have been bred to produce minimal levels of tetrahydrocannabinol (THC), the principal psychoactive constituent.
Many plants have been selectively bred to produce a maximum of THC (cannabinoids), which is obtained by curing the flowers. as a wild or escaped variety of the high-intoxicant type.
Male flowers are normally borne on loose panicles, and female flowers are borne on racemes. The genus Cannabis was formerly placed in the Nettle (Urticaceae) or Mulberry (Moraceae) family, and later, along with the Humulus genus (hops), in a separate family, the Hemp family (Cannabaceae sensu stricto). In the United States alone, it is believed that over 100 million Americans have tried cannabis, with 25 million Americans having used it within the past year.