Cannabis sativa (hemp)
Don't need the entire report?
Generate a print friendly version containing only the sections you need.Generate report
PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Cannabis sativa L., 1753
Preferred Common Name
Other Scientific Names
- Cannabis indica Lam.
- Cannabis ruderalis Janisch.
International Common Names
- English: marijuana
- Spanish: canamo; sinsemilla
- French: chanvre
- Russian: konoplya
- Arabic: hashish; kannab
- Chinese: ma fen; ta ma
- Portuguese: canhamo
Local Common Names
- Brazil: maconha
- Germany: Hanf
- Hungary: kender
- India: charas; ganja
- Italy: canapa
- Japan: asa
- Netherlands: hennep
- Poland: kenop
- South Africa: dagga
- Sweden: hampa
- CNIRU (Cannabis ruderalis)
- CNISA (Cannabis sativa)
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Urticales
- Family: Cannabaceae
- Genus: Cannabis
- Species: Cannabis sativa
Notes on Taxonomy and NomenclatureTop of page
The taxonomy of Cannabis remains in flux. In his original 1753 classification, Carl Linnaeus identified just one species, Cannabis sativa. Lamarck (1785) determined that Cannabis strains from India were distinct from the common hemp of Europe, based on stem and leaf morphology, and named the new species C. indica Lam. In a detailed review of the cannabis taxonomy problem Small and Cronquist (1976) returned to the monotypic view, defining a single highly variable species C. sativa, with a number of subspecies and varieties. Others continue with the polytypic view, with two or more additional species such as C. indica, C. ruderalis and C. afghanica (Schultes et al., 1974; McPartland et al., 2000; Hillig, 2005; McPartland, 2017). McPartland et al. (2000) indicates that the segregates are often misnamed, e.g. C. indica is misnamed C. sativa, and C. afghanica is misnamed C. indica or C. ruderalis.
Small and Cronquist (1976) based their Cannabis taxonomy, in part, on plant concentration of tetrahydrocannabinol (THC), which is the psychoactive compound unique to Cannabis. Since the 1940s, fibre hemp breeders have been reducing the THC content (Bocsa and Karus, 1997). Conversely, breeders of drug Cannabis have been increasing the THC content (Szendrei, 1997). Cannabis segregates can interbreed and hybridize, as shown by X C. intersita Sojak - a hybrid between C. ruderalis and C. sativa. Furthermore, C. sativa and C. indica escape cultivation and grow wild; these have been called C. ruderalis (Small and Cronquist, 1976). Here, Cannabis segregates are described as 'biotypes'.
DescriptionTop of page
Hemp is an annual herb and can grow to 1–5 m tall.
The seeds (achenes) are round to nearly lens-shaped, with a round base, surface green-brown to grey, marbled or unmarbled, with or without an abscission layer at the base, ranging in size from 1.5 to 4 mm long.
Young seedlings produce a pair of cotyledons, which are fleshy, somewhat oval (narrowed at the sessile base), with an entire margin. Cotyledons are followed by the first pair of true leaves, which are coarsely serrate, long, lanceolate, with a dark green upper surface and whitish-green lower surface.
During the early vegetative stage, seedlings form up to five true leaf pairs, oppositely arranged, with short internodes. The first true leaves are single leaflets, thereafter, leaves become palmately compound. The second leaf pair consist of three leaflets per leaf, the third leaf pair has five leaflets per leaf, and so on, up to eleven leaflets per leaf.
Later in the vegetative stage, stem elongation accelerates and internode distance increases. The stem normally does not branch, it is often hollow at maturity, its surface is generally ridged or fluted, and covered with a fine scabrous layer of cystolith trichomes. The root system is vigorous and centred by a taproot, with laterals.
Flowering stage begins with a change in phyllotaxis, from opposite to alternate, and stalk elongation is reduced. Plants are quite aromatic by this stage. Most plants are dioecious, although monoecious hemp cultivars have been bred in Europe. In a dioecious crop, male and female plants are usually present in more or less similar numbers. Male plants die 3-5 weeks earlier than female plants.
Early flower primordia appear at the base of petioles. Male primordia appear first. They have a curved claw shape, which grows into a pointed cone consisting of five fused tepals. Male (staminate) inflorescences are loosely branched cymose panicles. Tepals open and five anthers hang from flaccid filaments. Pollen grains are nearly spherical, smooth, 25-30 µm diameter, and light yellow. The female (pistillate) flowers are both axillary and terminal, the inflorescence tend to branch less and grow more compact and leafy. Leaves and bracts are often densely covered with resinous glandular hairs. Female flowers are inconspicuous - a pair of small, white styles emerging from each perigonal bract, they have one single-ovulate ovary. The fruit is a greyish-brown, shining achene, variously marked or plain, tightly embracing the seed. The fruit is ellipsoid 2-6 mm long and 2-4 mm in diameter
After pollination, the styles of pistillate flowers atrophy and necrose, while the bract swells. The perianth is papery, continuous, and closely appressed to the ovary. The perianth persists on the surface of the single seed (achene).
Hemp fibres are bast or phloem cells, only 10 µm wide, but up to 7.5 cm long. The fibres overlap in bundles containing from 10-40 cells per bundle. Fibre bundles often run the entire length of plants. Approximately 25 bundles lie around stems, embedded in a ring of phloem parenchyma.
The morphological descriptions of the 'biotypes' presented below are adapted from work by Schultes et al. (1974), Small and Cronquist (1976) and McPartland et al. (2000).
Cannabis sativa [syn. C. sativa subsp. sativa]:
Plants tall (up to 6 m), stems smooth and hollow, laxly branched with long internodes; petioles short, usually 5-9 leaflets per leaf, leaflets lanceolate, largest leaflets averaging 136 mm long (length/width ratio = 7.5); racemes have long internodes, and achenes are partially exposed; achenes (seeds) usually 3.7 mm long, somewhat lens-shaped with a blunt base, surface dull light-to-dark green and usually unmarbled, seeds usually adherent to plants at maturity. Cultivated for fibre, oil, and sometimes for drugs.
Cannabis indica [syn. C. sativa subsp. indica]:
Plants shorter (under 3 m), stems smooth and nearly solid, densely branched with shorter internodes; petioles shorter, usually 7-11 leaflets per leaf; leaflets narrow lanceolate, largest leaflets averaging 92 mm long (l/w ratio = 10); achenes averaging 3.7 mm long, less lens-shaped, with a more rounded base, surface green-brown and marbled or unmarbled, with or without an abscission layer. Cultivated primarily for drugs but also used for fibre and oil.
Cannabis ruderalis [syn. C. sativa var. spontanea]:
Plants small (usually under 0.5 m), stems smooth and hollow, occasionally unbranched; petioles short, usually 5-7 leaflets per leaf, leaflets elliptic, largest leaflets averaging 60 mm long (l/w ratio = 6); achenes small with a pronounced abscission structure at the base, surface dull green and marbled, abscission layer fleshy with oil-producing cells, seeds readily shed from plant. Feral, not cultivated.
Cannabis 'afghanica' [syn. C. sativa var. afghanica]:
Plants short (under 1.5 m), stems ribbed and nearly solid, densely branched with short internodes; petioles long, usually 7-11 leaflets per leaf, leaflets dark green and broadly oblanceolate, largest leaflets averaging 130 mm (l/w ratio =5); racemes have short internodes, and achenes are not exposed; nested, compound bracts sometimes produced; achenes usually <3.0 mm long, nearly round with a blunt base, surface shiny grey and marbled. Cultivated for drugs, primarily hashish.
DistributionTop of page
The exact origin of hemp and its cultivation are not very clear; however, both historians and archaeologists agree that hemp was one of the first non-food crops to be cultivated. It is thought that the plant probably originates from temperate central Asia. DeCandolle (1886) ascribed a very extensive region to the plant - suggesting that C. sativa originated in a region between the Caspian Sea and Lake Baikal; Vavilov (1926) believes it to be an area around the Altai Mountains; and McPartland et al. (2000) proposes the southern Tien Shan Mountains. Authors from India favour an origin in the Himalayas, and Chinese authors propose sites along the Yangtze or Yellow rivers.
There is strong archaeological evidence of the widespread use of hemp in China as an economic crop by around 4500 BC. The vast majority of hemp fibre remains have been recovered from archaeological sites in China. The oldest written record of the use of hemp is a Chinese herbal from the third millennium BC, in which the medicinal use of hemp was described. In a tomb in the Shaanxi Province of China in 1957, archaeologists discovered a piece of paper containing hemp fibre, dated to 140–87 BC. This is considered to be the oldest piece of paper ever recovered. According to Vavilov, domestication of hemp probably occurred independently in several centres in northeast Asia around six millennia ago. By around 1000 BC, hemp had probably migrated west and south with nomads and traders and spread over India, the Middle East, Asia Minor, Africa and Europe. In Egypt, the presence of hashish was found in the body tissues of mummies, dating back to about 1000 BC. The Greeks and Romans used hemp for the production of rope and coarse fabric. They probably did not use it as a drug. In Persia and Arabia they certainly used hemp as a drug because the term ‘hashish’ is Arabian and taken from ‘hashish al kief’, which means ‘dried herb of pleasure.' The first record of drug use of hempwas the prehistoric Scythians (Herodotus, 1906). Drug cultivation spread from India to Arabia, eastern Africa, southern Africa, and South-East Asia. During the 1800s, servants from India carried seeds to Jamaica, and from here drug cultivation spread within the Gulf of Mexico.
There is considerable evidence for the diffusion of hemp in Europe and the Middle East. European fibre hemp cultivation expanded in the 1500s and 1600s, to meet the demand for ropes and sails in the shipping industry and European explorers spread hemp cultivation throughout the Americas, Australia, and western Africa. From the 16th to the 18th centuries, hemp was an important fibre crop in Europe and North America. Hemp production declined in the 19th and 20th centuries due to the large-scale cultivation of cotton, the advent of synthetic fibres and because the growing of hemp has been made illegal in many countries.
Today the distribution of hempcultivation is poorly documented. The FAO cites only 16 hemp-growing countries (FAO, 2013). Statistics by the EU are more accurate although the data are not recent (Mignoni, 1997). Nova Institute (Karus et al., 2000) supplements the EU statistics with results of monitoring 31 countries. A list of major centres of cultivation for a minor crop such as hemp, is liable to change and become out of date. The drug cannabis, for instance, is grown almost globally (the ODCCP cites 120 countries), but few countries are consistent and have significant exportation.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|China||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 30,000 MT (F)|
|China||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 45,000 MT (F)|
|-Nei Menggu||Present||FAO, 2000|
|Japan||Present||FAO, 2009||Hemp Tow Waste production (2008) 0 MT (F)|
|Korea, DPR||Present||FAO, 2000|
|Korea, Republic of||Present||FAO, 2009||Hemp Tow Waste production (2008) 23 MT (F)|
|Syria||Present||FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|Turkey||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 55 MT (F)|
|Turkey||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 45 MT (F)|
|-British Columbia||Present||Hanks, 1999|
|-Nova Scotia||Present||Hanks, 1999|
|Chile||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 4,385 MT (F)|
|Chile||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 1,300 MT (F)|
|Austria||Present||FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|Belarus||Present||Karus et al., 2000|
|Belgium||Present||Karus et al., 2000|
|Bulgaria||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|Bulgaria||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 0 MT (M)|
|Croatia||Present||FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|Cyprus||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 0 MT (F)|
|Cyprus||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 0 MT (F)|
|Denmark||Present||Karus et al., 2000|
|France||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 7,100 MT (F)|
|France||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 5,500 MT (F)|
|Germany||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|Germany||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 0 MT (M)|
|Hungary||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 500 MT (F)|
|Hungary||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 450 MT (F)|
|Italy||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 1,281 MT (F)|
|Italy||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 0 MT (M)|
|Netherlands||Present||Karus et al., 2000|
|Poland||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 50 MT (F)|
|Poland||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 20 MT (F)|
|Portugal||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|Portugal||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 0 MT (M)|
|Romania||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 2,000 MT (F)|
|Romania||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 100 MT (F)|
|Russian Federation||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 1,500 MT (F)|
|Russian Federation||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 331 MT|
|-Central Russia||Present||FAO, 2000; Karus et al., 2000|
|-Northern Russia||Present||FAO, 2000; Karus et al., 2000|
|-Southern Russia||Present||FAO, 2000; Karus et al., 2000|
|Spain||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 15,000 MT (F)|
|Spain||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 8 MT (F)|
|Sweden||Present||FAO, 2009||Hemp Tow Waste production (2008) 0 MT (M)|
|UK||Present||FAO, 2000; Karus et al., 2000|
|Ukraine||Present||FAO, 2009; FAO, 2009||Hemp Tow Waste production (2008) 1,000 MT (F)|
|Ukraine||Present||FAO, 2009; FAO, 2009||Hempseed production (2008) 600 MT (F)|
Habitat ListTop of page
Biology and EcologyTop of page
C. sativa is an annual herb, and the seed germinates 3-7 days after absorbing water. Early vegetative growth is often slow, but later growth may be quite rapid. Generally, canopy closure (when leaves of adjacent plants mesh together and shade the soil) occurs when fibre crops are approximately 50 cm in height.
Duke (1985) determined that optimal growth of C. sativa occurs at 14.3°C. It has a growth period of 2-10 months, which is dependent on the latitude. C. sativa has an extensive root system, and is able to tolerate dry conditions, although it does not thrive. C. sativa also grows poorly in wetlands or saturated soil. Duke (1985) found that C. sativa has optimum growth in areas receiving an annual rainfall of 970 mm.
C. sativa grows well in bright sunlight. McPartland et al. (2000) describes good plant growth at 14,000-18,000 lx, or 215 W/m. It flowers in the autumn, when the photoperiod drops below 12-13 hours per day, depending on the variety and location. C. sativa tolerates UV radiation, and under high UV-B conditions the production of THC is enhanced (Lydon et al., 1987).
C. sativa grows from sea level to 3700 m in altitude, and from the equator to approximately 63° latitude (such as in Finland). Fibre hemp cultivars grow well at 40-55° latitude, and they perform poorly in semi-tropical and tropical latitudes. However, drug varieties were bred in semitropical and tropical locations, and have poor growth at high latitudes (above 45°), because frost often kills the plants before flowering.
C. sativa grows well in nutrient rich, well drained, well structured, silty loam soil with high organic matter. The plant is a nitrophile and requires much nutrients. Fibre crops require high levels of nitrogen and potassium, and in descending order of importance calcium, phosphorous and magnesium. However, seed crops extract less potassium and more phosphorous from the soil, and drug crops have a high demand for phosphorus (Frank and Rosenthal, 1978). Duke (1985) suggests that a soil pH of 6.5 is optimal.
Natural enemiesTop of page
Threatened SpeciesTop of page
Risk and Impact FactorsTop of page Impact outcomes
- Ecosystem change/ habitat alteration
UsesTop of page
The long, strong, mildew-resistant fibre in hemp was traditionally used for rope, sails, tarpaulin, canvas bags, and carpets. Fine yarn can be spun for clothing, handbags, and other textiles. The low lignin level present in hemp fibre and hurds make these materials ideal for production of paper, fibreboard, composite wood products; or may be mixed with lime to create reinforced concrete. The fibres also serve as a fibreglass substitute, for pressed insulation and moulded panels for the car industry.
The seed is technically an achene, a small, dry nut. C. sativa plants are prolific seeders; nearly half the weight of a well-pollinated female turns to seed. For example field-grown crops yield an average of 400 g seeds per plant, or about 22,000 seeds per plant (McPartland et al., 2000).
Approximately one-third of hempseed is oil, which is used in lighting, lubrication, soaps, detergents and cosmetic creams. The fatty acids are quick drying and so hemp oil is useful for paints, varnishes and printing inks. Hemp oil can also be burned as a fuel.
In China, hempseed is commonly eaten, roasted or raw. Hemp oil contains a high percentage of essential fatty acids, it is therefore a valuable food supplement, and is useful in salad dressings and margarine. After the oil has been pressed out of the seed, the remaining seed cake is rich in protein and is suitable for use as a flour or an animal feed Pate, 1999.
Two types of drug are produced: (i) hashish, pure resin, which is scraped from the flowering tops of the plant, the oil obtained from resin is known as 'hashish oil’; and (ii) marijuana, dried unfertilized inflorescences of female plants, or the dried leaves and flowers of the male and female plants. More resin is produced in tropical than in temperate climates
Tetrahydrocannabinol (THC) is the primary active ingredient in the drug cannabis, but THC activity is modulated by dozens of other cannabinoids, terpenoids, and flavonoids. These compounds are synthesized in specialized leaf hairs called glandular trichomes, which are most dense on the surface of the leafy female flowers. The upper head of the glands consists of secretory cells and is covered by a tough but distensible sheath. Secretion of cannabinoids, terpenoids, and flavonoids swell the sheath into a spherical head up to 120 µm in diameter.
Air-dried herbal products (such as marijuana, sinsemilla) dominate the illicit market in North America, South America, and South Africa. Hashish dominates the market in Western Europe; the source is primarily Morocco (some 400 tonnes annually), and Pakistan and Afghanistan (260 tonnes), according to the UNDCP (1997). Hash oil maintains niche markets in Canada, Nepal, western Europe and Oceania (ODCCP, 2000).
For legitimate medicinal use, clinical trials have demonstrated the efficacy of the drug cannabis for treating many diseases and syndromes, including arthritis, muscle spasms, headaches, menstruation, multiple sclerosis, epilepsy, anorexia, glaucoma, insomnia, anxiety, depression and even drug addiction.
C. sativa has been used in traditional medicine in Tibet, and also in Ayurveda medication. In Western medicine, the use of C. sativa began with O'Shaughnessy's research published in the 1830s, and terminated with the USA Marihuana Tax Act of 1937. In the past ten years, however, the drug has been re-introduced. Synthetic forms of THC are widely prescribed, and several pharmaceutical companies are currently developing cannabis plant extracts.
The essential oil (which contains no THC) can be used in cosmetics, perfumes, food additives, and it may be fractionated for pharmaceutical use. The oil has antibacterial, antifungal and pest-repellent properties, and is being developed as an organic pesticide (McPartland, 1997).
Uses ListTop of page
Animal feed, fodder, forage
- Fodder/animal feed
Drugs, stimulants, social uses
- Miscellaneous drugs, stimulants and social uses
- Essential oils
- Source of medicine/pharmaceutical
ReferencesTop of page
Able E, 1980. Marijuana: The First 12,000 Years. NY, USA: Plenum Press.
B=csa I; Karus M, 1997. Der Hanfanbau: Botanik, Sorten, Anbau und Ernte. Mnller Verlag, Heildelberg. 173 pp. [The Cultivation of Hemp: Botany, Varieties, Cultivation and Harvesting, 1998]. Hemptech, Sebastopol, CA.
Canapasemi G, 1988. Hemp fiber cultivation. Sinsemilla Tips, 8(3):49-57.
Clarke RC, 1998. Hashish! Los Angeles,USA: Red Eye Press.
de Meijer EPM, 1999. Cannabis germplasm resources. In: Ranalli P, ed. Advances in Hemp Research. NY, USA: Haworth Press, 133-151.
DEA, 1998. Domestic Cannabis Eradication/Suppression Program, 1997. Washington, DC, USA: Drug Enforcement Administration.
Dempsey JM, 1975. Hemp. In: Fiber Crops. Gainesville, FL, USA: University of Florida Press.
Duke JA, 1985. CRC Handbook of Medicinal Herbs. Boca Raton, FL, USA: CRC Press.
FAO, 2000. Food and Agriculture Organization of the United Nations, Yearbook. Production. <. target="_blank">http://apps.fao.org/default.html>.
Frank M; Rosenthal E, 1978. Marijuana Grower's Guide. Berkeley, CA, USA: And/Or Press.
Gettman J; Armentano P, 1998. The 1998 marijuana crop report. National Organization for the Reform of Marijuana Laws, <. target="_blank">http://www.norml.org/home.html>.
Hanks J, 1999. Year end special. Hemp Commerce & Farming Report Vol 1, Issue 7 <. target="_blank">http://www.hemphasis.com/>.
Herodotus, 1906. Herodotus IV (Melpomene). Reprint. Cambridge, UK: University Press.
Karus M; Kaup M, 1999. Use of natural fibres in the German automotive industry. J. International Hemp Association, 6(2):72-75.
Karus M; Kaup M; Lohmeyer D, 2000. Study on markets and prices for natural fibres. Nova Institute Report for Bioresource Hemp Conference. <. target="_blank">http://www.bioresource-hemp.de/>.
Lydon J; Teramura AH; Coffman CB, 1987. UV-B radiation effects on photosynthesis, growth and cannabinoid production of two Cannabis sativa chemotypes. Photochemistry & Photobiology, 46(2):201-206.
McPartland JM, 1997. Cannabis as a repellent crop and botanical pesticide. J. International Hemp Association, 4(2):89-94.
Meier C; Mediavilla V, 1998. Factors influencing the yield and the quality of hemp (Cannabis sativa L.) essential oil. J. International Hemp Association, 5(1):16-20.
Mignoni G, 1997. Cannabis as a licit crop: recent developments in Europe. Bulletin on Narcotics, 49(1-2):23-43. <. target="_blank">http://www.undcp.org/index.html>.
ODCCP, 2000. Global Illicit Drug Trends 2000. Office for Drug Control and Crime Prevention, United Nations, New York, 219 pp. <. target="_blank">http://www.undcp.org/index.html>.
Pate DW, 1999. Hemp seed: a valuable food source. In: Ranalli P, ed. Advances in Hemp Research. NY, USA: Haworth Press, 243-255.
Schultes RE; Klein WM; Plowman T; Lockwood TE, 1974. Cannabis: an example of taxonomic neglect. Bot. Mus. Leaflet. Harv. Univ., 23:337-367.
Small E; Cronquist A, 1976. A practical and natural taxonomy for Cannabis. Taxon, 25:405-435.
Stockberger WW, 1915. Drug plants under cultivation. USDA Farmer's Bulletin No. 663. Washington, D.C.: USDA.
Szendrei K, 1997. Cannabis as an illicit crop: recent developments in cultivation and production quality. Bulletin on Narcotics, 49(1-2):1-21. <. target="_blank">http://www.undcp.org/index.html>.
UNDCP, 1997. Cannabis as an illicit narcotic crop: a review of the global situation of cannabis consuption, trafficking and production. Bulletin on Narcotics, 49(1-2):43-83. <. target="_blank">http://www.undcp.org/index.html>.
Wirstshafter D, 1997. Nutritional value of hemp seed and hemp seed oil. In: Mathre ML, ed. Cannabis in Medical Practice. NC, USA: McFarland & Co., Jefferson, 181-191.
Wolf B, 1999. The Fertile Triangle: The Interrelationship of Air, Water, and Nutrients in Maximizing Soil Productivity. New York, USA: Haworth Press.
Distribution MapsTop of page
Unsupported Web Browser:
One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Please consider upgrading your browser to the latest version or installing a new browser.
More information about modern web browsers can be found at http://browsehappy.com/