Cannabis is a genus of annual, dioecious flowering herbs in the family Cannabaceae (order Rosales), widely accepted as native to Asia and first domesticated approximately 12,000 years ago in East Asia during the early Neolithic period. The genus is among the most economically and culturally significant plant groups in human history, cultivated for fibre, food, medicine, and as a source of psychoactive compounds.
Plants are herbaceous and produce palmately compound or digitate leaves with serrate leaflets — typically seven to nine per leaf at maturity, though the count varies by variety and growing condition. A distinctive venation pattern in the leaf serrations allows reliable identification of Cannabis foliage even from fragmentary samples. Individual plants are either male or female (dioecious), and the genus is wind-pollinated.
Cannabis produces a unique family of terpeno-phenolic compounds called cannabinoids. At least 85 distinct cannabinoids have been isolated from the plant; the two most abundant are cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). Only THC is psychoactive. Plants are classified by their chemical phenotype (chemotype): non-drug types produce low THC and high CBD, while drug types produce high THC and low CBD. This THC:CBD ratio is genetically determined and remains fixed throughout a plant's life, though overall cannabinoid yield is influenced by environmental conditions.
The number of species within Cannabis remains disputed. As many as three species are recognised — Cannabis sativa, C. indica, and C. ruderalis — though some treatments include C. ruderalis within C. sativa, or regard all three as subspecies of a single species. GBIF currently recognises one accepted species under the genus. The debate reflects the absence of physiological barriers to interbreeding across the genus combined with morphological and ecological divergence that may reflect geographic isolation rather than true speciation.
Etymology
The genus name Cannabis derives from a Scythian word. The ancient Greeks first documented the plant's use by observing Scythian funerals, during which cannabis was burned and inhaled. The Greek form passed into Latin and subsequently into most European languages.
Distribution
Cannabis is widely accepted as indigenous to the continent of Asia, with genetic and archaeological evidence pointing to East Asia as the site of first domestication approximately 12,000 years ago. From Central and East Asia, use spread through the Islamic empire to North Africa, and in 1545 the plant was introduced to the western hemisphere when Spanish colonists brought it to Chile. It is now cultivated or naturalised on every inhabited continent.
History
Cannabis has one of the longest documented relationships with humanity of any cultivated plant. Archaeological evidence places first domestication in East Asia around 12,000 years ago during the early Neolithic. The oldest written account of its psychoactive use appears in Herodotus's Histories (c. 440 BCE), which describes Scythian steam baths fuelled by cannabis flowers. Chinese texts including the Shennong Bencaojing (3rd century AD) document its medicinal and psychoactive properties. It reached North Africa via the Islamic empire and the Americas in 1545. The first cannabinoid to be isolated was cannabinol (CBN) in the late 1800s, with full structural characterisation and synthesis completed by 1940 — laying the groundwork for modern cannabinoid pharmacology.
Cultivation
Cannabis cultivars divide broadly into fibre/seed types (hemp — selected for low THC, high fibre yield) and drug types (selected for high THC or, more recently, high CBD). The species is an annual herb grown from seed in a wide range of climates. Chemical phenotype (the THC:CBD ratio) is genetically fixed per cultivar, though total cannabinoid production responds to light, temperature, and growing conditions. Industrial hemp is cultivated for bast fibre used in textiles, rope, and construction materials, as well as for seeds rich in oils and protein.
Cultural Uses
Cannabis has served as a fibre crop (hemp) for rope, cloth, and paper across cultures for millennia. Its seeds and oils are used as food, and its leaves have been consumed as vegetables. The plant is the source of hashish and hash oil. Medicinally, cannabinoids — particularly CBD and THC — are used to treat pain, nausea, epilepsy, and other conditions. As a recreational drug it is one of the most widely used psychoactive substances globally, known by numerous vernacular names including marijuana, pot, and weed.
Taxonomy Notes
Cannabis was historically placed in the nettle family (Urticaceae) or mulberry family (Moraceae). It was later reassigned, along with the closely related genus Humulus (hops), to the hemp family Cannabaceae sensu stricto. Phylogenetic analyses based on chloroplast DNA restriction sites and gene sequencing indicate that Cannabaceae sensu stricto is nested within the former Celtidaceae, and that the two families should be merged into a single monophyletic Cannabaceae sensu lato. The species boundary question within Cannabis remains unresolved: while plants from widely divergent geographic sources are interfertile (no physiological barrier to interbreeding), geographic barriers such as the Himalayas may have promoted divergence before human intervention. GBIF accepts the genus as monotypic at the species level in its current backbone.
