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Cannabis
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Urticales
Family:	Cannabaceae
Genus:	Cannabis L.
Species
Cannabis sativa L.

This article is about the plant genus Cannabis. For use as a psychoactive drug, see Cannabis (drug). For use as a therapeutic drug, see Medical Cannabis. For non-drug cultivation and uses, see Hemp.

Cannabis is a genus of flowering plant that includes one or more species. The plant is believed to be indigenous to Central Asia, China, and the north-west Himalayas. The common name for Cannabis is hemp, although this term is sometimes used to refer only to strains cultivated for "industrial" (non-drug) use. Cannabis plants produce a unique family of compounds called cannabinoids, several of which produce mental and/or physiological effects when consumed. The crude drug usually comes in the form of dried flowers and leaves, resin (hashish), or various extracts.. The cultivation or possession of Cannabis for drug purposes is outlawed in most countries.

Species

Cannabis sativa L.

Putative species:

• C. indica Lam.
• C. ruderalis Janisch.

Description

Cannabis is an annual, dioecious, flowering herb. The leaves are palmately compound, with serrate leaflets. The first pair of leaves usually have a single leaflet, the number gradually increasing up to a maximum of about thirteen leaflets per leaf (usually seven or nine), depending on variety and growing conditions. At the top of a flowering plant, this number again diminishes to a single leaflet per leaf. The lower leaf pairs usually occur in an opposite leaf arrangement and the upper leaf pairs in an alternate arrangement on the main stem of a mature plant.

Cannabis usually has imperfect flowers with staminate "male" and pistillate "female" flowers occuring on separate plants, although hermaphroditic flowers sometimes occur. Male flowers are borne on loose panicles, and female flowers are borne on racemes. It is not unusual for individual plants to bear both male and female flowers in some strains, a condition called monoecy. On monoecious plants, flowers of both sexes may occur on separate inflorescences, or on the same inflorescence.

Cannabinoids, terpenoids, and and other volatile compounds are secreted by glandular trichomes that occur most abundantly on the floral calyxes and bracts of female plants.

All strains of Cannabis are wind-pollinated and produce "seeds" that are technically called achenes. . Most strains of Cannabis are short day plants , with the possible exception of C. sativa subsp. sativa var. spontanea (= C. ruderalis), which is commonly described as "auto-flowering" and may be day-neutral.

Cannabis is naturally diploid, having a chromosome complement of 2n=20, although polyploid individuals have been artificially produced.

Taxonomy

The genus Cannabis was formerly placed in the Nettle (Urticaceae) or Mulberry (Moraceae) family, but is now considered along with hops (Humulus sp.) to belong to the Hemp family (Cannabaceae).

Various types of Cannabis have been described, and classified as species, subspecies, or varieties:

• plants cultivated for fiber and seed production, described as low-intoxicant, non-drug, or fiber types
• plants cultivated for drug production, described as high-intoxicant or drug types
• escaped or wild forms of either of the above types.

Cannabis plants produce a unique family of terpeno-phenolic compounds called cannabinoids, which produce the "high" one experiences from smoking marijuana. The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or Δ-tetrahydrocannabinol (THC), but only THC is psychoactive. Since the early 1970's, Cannabis plants have been categorized by their chemical phenotype or "chemotype," based on the overall amount of THC produced, and on the ratio of THC to CBD. Although overall cannabinoid production is influenced by environmental factors, the THC/CBD ratio is genetically determined and remains fixed throughout the life of a plant. Non-drug plants produce relatively low levels of THC and high levels of CBD, while drug plants produce high levels of THC and low levels of CBD. When plants of these two chemotypes cross-pollinate, the plants in the first filial (F₁) generation have an intermediate chemotype and produce similar amounts of CBD and THC. Female plants of this chemotype may produce enough THC to be utilized for drug production.

Whether the drug and non-drug, cultivated and wild types of Cannabis constitute a single, highly variable species, or the genus is polytypic with more than one species, has been a subject of debate for well over two centuries. This is a contentious issue because there is no universally accepted definition of a species. One widely applied criterion for species recognition is that species are "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups." Populations that are physiologically capable of interbreeding, but morphologically or genetically divergent and isolated by geography or ecology, are sometimes considered to be separate species. Physiological barriers to reproduction are not known to occur within Cannabis, and plants from widely divergent sources are interfertile. It remains controversial whether sufficient morphological and genetic divergence occurs within the genus as a result of geographical or ecological isolation to justify recognition of more than one species.

Early classifications

The Cannabis genus was first classified using the "modern" system of taxonomic nomenclature by Carolus Linnaeus in 1753, who devised the system still in use for the naming of species. He considered the genus to be monotypic, having just a single species that he named Cannabis sativa L. (L. stands for Linnaeus, and indicates the authority who first named the species). Linnaeus was familiar with European hemp, which was widely cultivated at the time. In 1785, noted evolutionary biologist Jean-Baptiste de Lamarck published a description of a second species of Cannabis, which he named Cannabis indica Lam. Lamarck based his description of the newly named species on plant specimens collected in India. He described C. indica as having poorer fiber quality than C. sativa, but greater utility as an inebriant. Additional Cannabis species were proposed in the 19th century, including strains from China and Vietnam (Indo-China) assigned the names Cannabis chinensis Delile, and Cannabis gigantea Delile ex Vilmorin. However, many taxonomists found these putative species difficult to distinguish. In the early 20th century, the single-species concept was still widely accepted, except in the Soviet Union where Cannabis continued to be the subject of active taxonomic study. The name Cannabis indica was listed in various Pharmacopoeias, and was widely used to designate Cannabis suitable for the manufacture of medicinal preparations.

20th Century

In 1924, Russian botanist D.E. Janischevsky concluded that ruderal Cannabis in central Russia is either a variety of C. sativa or a separate species, and proposed C. sativa L. var. ruderalis Janisch. and Cannabis ruderalis Janisch. as alternative names. In 1929, renown plant explorer Nikolai Vavilov assigned wild or feral populations of Cannabis in Afghanistan to C. indica Lam. var. kafiristanica Vav., and ruderal populations in Europe to C. sativa L. var. spontanea Vav. In 1940, Russian botanists Serebriakova and Sizov proposed a complex classification in which they also recognized C. sativa and C. indica as separate species. Within C. sativa they recognized two subspecies: C. sativa L. subsp. culta Serebr. (consisting of cultivated plants), and C. sativa L. subsp. spontanea (Vav.) Serebr. (consisting of wild or feral plants). Serebriakova and Sizov split the two C. sativa subspecies into 13 varieties, including four distinct groups within subspecies culta. However, they did not divide C. indica into subspecies or varieties. This excessive splitting of C. sativa proved too unwieldy, and never gained many adherents.

In the 1970's, the taxonomic classification of Cannabis took on added significance in North America. Laws prohibiting Cannabis in the United States and Canada specifically named products of C. sativa as prohibited materials. Enterprising attorneys for the defense in a few drug busts argued that the seized Cannabis material may not have been C. sativa, and was therefore not prohibited by law. Attorneys on both sides recruited botanists to provide expert testimony. Among those testifying for the prosecution was Dr. Ernest Small, and Dr. Richard E. Schultes and others testified for the defense. The botanists engaged in heated debate (outside of court), and both camps impugned the other's integrity. The defense attorneys were not often successful in winning their case, because the intent of the law was clear.

In 1976, Canadian botanist Ernest Small and American taxonomist Arthur Cronquist published a taxonomic revision that recognizes a single species of Cannabis with two subspecies: C. sativa L. subsp. sativa, and C. sativa L. subsp. indica (Lam.) Small & Cronq. The authors hypothesized that the two subspecies diverged primarily as a result of human selection; C. sativa subsp. sativa was presumably selected for traits that enhance fiber or seed production, whereas C. sativa subsp. indica was primarily selected for drug production. Within these two subspecies, Small and Cronquist described C. sativa L. subsp. sativa var. spontanea Vav. as a wild or escaped variety of low-intoxicant Cannabis, and C. sativa subsp. indica var. kafiristanica (Vav.) Small & Cronq. as a wild or escaped variety of the high-intoxicant type. This classification was based on several factors including interfertility, chromosome uniformity, chemotype, and numerical analysis of phenotypic characters.

Professors William Emboden, Loran Anderson, and Harvard botanist Richard E. Schultes and coworkers also conducted taxonomic studies of Cannabis in the 1970's, and concluded that stable morphological differences exist that support recognition of at least three species, C. sativa, C. indica, and C. ruderalis. For Schultes, this was a reversal of his previous interpretation that Cannabis is monotypic, with only a single species. According to Schultes' and Anderson's descriptions, C. sativa is tall and laxly branched with relatively narrow leaflets, C. indica is shorter, conical in shape, and has relatively wide leaflets, and C. ruderalis is short, branchless, and grows wild in central Asia. This taxonomic interpretation was embraced by Cannabis aficionados who commonly distinguish narrow-leafed "sativa" drug strains from wide-leafed "indica" drug strains.

Ongoing research

Molecular analytical techniques developed in the late twentieth century are being applied to questions of taxonomic classification. This has resulted in many reclassifications based on evolutionary systematics. Several studies of Randomly Amplified Polymorphic DNA (RAPD) and other types of genetic markers have been conducted on drug and fiber strains of Cannabis, primarily for plant breeding and forensic purposes. Dutch Cannabis researcher E.P.M. de Meijer and coworkers described some of these RAPD studies as showing an "extremely high" degree of genetic polymorphism between and within populations, suggesting a high degree of potential variation for selection, even in heavily selected hemp cultivars. They also commented that these analyses confirm the continuity of the Cannabis gene pool throughout the studied accessions, and provide further confirmation that the genus comprises a single species.

Karl W. Hillig, a graduate student in the laboratory of long-time Cannabis researcher Paul G. Mahlberg at Indiana University, conducted a systematic investigation of genetic, morphological, and chemotaxonomic variation among 157 Cannabis accessions of known geographic origin, including fiber, drug, and feral populations. In 2004, Hillig and Mahlberg published a chemotaxomic analysis of cannabinoid variation in their Cannabis germplasm collection. They used gas chromatography to determine cannabinoid content and to infer allele frequencies of the gene that controls CBD and THC production, within the studied populations. Hillig and Mahlberg concluded that the patterns of cannabinoid variation support recognition of C. sativa and C. indica as separate species, but not C. ruderalis. The authors assigned fiber/seed landraces and feral populations from Europe, central Asia, and Asia Minor to C. sativa. Narrow-leaflet and wide-leaflet drug accessions, southern and eastern Asian hemp accessions, and feral Himalayan populations were assigned to C. indica. In 2005, Hillig published a genetic analysis of the same set of accessions (this paper was submitted ahead of his 2004 manuscript with Mahlberg, but was delayed in publication), and proposed a three-species classification, recognizing C. sativa, C. indica, and (tentatively) C. ruderalis. In his doctoral dissertation published the same year, Hillig stated that principal components analysis of phenotypic (morphological) traits failed to differentiate the putative species, but that canonical variates analysis resulted in a high degree of discrimination of the putative species and infraspecific taxa. Another paper published by Hillig on chemotaxonomic variation in the terpenoid content of the essential oil of Cannabis revealed that several wide-leaflet drug strains in their collection had relatively high levels of certain sesquiterpene alcohols, including guaiol and isomers of eudesmol, that set them apart from the other putative taxa. Hillig concluded that the patterns of genetic, morphological, and chemotaxonomic variation support recognition of C. sativa and C. indica as separate species. He also concluded there is little support to treat C. ruderalis as a separate species from C. sativa at this time, but more research on wild and weedy populations is needed because they were underrepresented in his collection.

As of 2007, most taxonomy web sites continue to list Cannabis as a single species.

Popular usage

The scientific debate regarding taxonomy has had little effect on the terminology in widespread use among cultivators of drug-type Cannabis. Cultivators recognize three distinct varieties based on morphology, native range, and subjective psychoactive characteristics. "Cannabis sativa" is the term used to describe the most widespread variety, which is tall, conical, and found in warm lowland regions. "Cannabis indica" is used to describe shorter, bushier plants adapted to cooler climates and highland environments. "Cannabis ruderalis" is the term used to describe the short, tough plants that grow wild in central Asia.

Breeders, seed companies, and cultivators of drug type Cannabis often describe the ancestry or gross phenotypic characteristics of cultivars by categorizing them as pure indica, mostly indica, indica/sativa, mostly sativa, or pure sativa.

In September of 2005, New Scientist reported that researchers at the Canberra Insitute of Technology had identified a new subspecies of Cannabis, based on analysis of mitochondrial and chloroplast DNA. . The New Scientist story, which was picked up by many news agencies and web sites, indicated that the research was to be published in the journal Forensic Science International. As of November 2006, the work has not appeared in that journal.

Geographical distribution

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Wild cannabis

Wild C. sativa subsp. indica is mainly confined to hash producing areas such as Afghanistan, and parts of Morocco. Wild C. sativa subsp. sativa shows great local variation; for example, in warm places, it can reach heights up to 20 feet (6 m) tall, but in colder climates it can be as short as 1 foot (30 cm) in height. Almost every single flower branch bears a seed. The wild C. sativa subsp. sativa has long, thin and airy buds and a Christmas tree shape structure. Wild C. sativa subsp. indica remains compact and bushy with thick buds for the most part, and is sometimes used by the locals for hashish production. Generally, there are far fewer seeds in wild C. sativa subsp. indica.

In many areas, wild or naturalized populations of Cannabis are considered invasive species, and are often targeted by government-sponsored eradication programmes.

Reproduction

Breeding systems

Cannabis has been described as predominantly dioecious , although some monoecious varieties have also been described Subdioecy (the occurrence of monoecious individuals and dioecious individuals within the same population) is widespread. Many populations have been described as sexually labile.

As a result of intensive selection in cultivation, Cannabis exhibits many sexual phenotypes, which can be described in terms of the ratio of female to male flowers occurring in the individual or typical in the cultivar. Dioecious varieties are preferred for drug production, where the female plants are preferred. Dioecious varieties are also preferred for textile fiber production, whereas monecious varieties are preferred for pulp and paper production. It has been suggested that the presence of monoecy can be used to differentiate between licit crops of monoecious hemp and illicit dioecious drug crops.

Mechanisms of sex determination

Cannabis has been described as having one of the most complicated mechanisms of sex determination among the dioecious plants. Many models have been proposed to explain sex determination in Cannabis.

Based on studies of sex reversal in hemp, it was first reported in 1924 by K. Hirata that an XY sex-determination system is present. At the time, the XY system was the only known system of sex determination. The X:A system was first described in Drosophila spp in 1925. Soon thereafter, Schaffner disputed Hirata's interpretation, and published results from his own studies of sex reversal in hemp, concluding that an X:A system was in use and that futhermore sex was strongly influenced by environmental conditions.

Since then, many different types of sex determination system have been discovered, particularly in plants. Dioecy is relatively uncommon in the plant kingdom, and a very low percentage of dioecious plant species have been determined to use the XY system. In most cases where the XY system is found it is believed to have evolved recently and independently.

Since the 1920's, a number of sex determination models have been proposed for Cannabis. Ainsworth describes sex determination in the genus as using "an X/autosome dosage-type."

The question of whether heteromorphic sex chromosomes are indeed present is most conveniently answered if such chromosomes were clearly visible in a karyotype. Cannabis was one of the first plant species to be karyotyped, however, this was in a period when karyotype preparation was primitive by modern standards (see History of Cytogenetics). Heteromorphic sex chromosomes were reported to occur in staminate individuals of dioecious 'Kentucky' hemp, but were not found in pistillate individuals of the same variety. Dioecious 'Kentucky' hemp was assumed to use an XY mechanism. Heterosomes were not observed in analyzed individuals of monoecious 'Kentucky' hemp, nor in an unidentified German cultivar. These varieties were assumed to have sex chromosome composition XX. But according to other researchers no modern karyotype of Cannabis had been published as of 1996. Proponents of the XY system state that Y chromosome is slightly larger than the X, but difficult to differentiate cytologically.

More recently, Sakamoto and various co-authors have used RAPD to isolate several genetic marker sequences that they name Male-Associated DNA in Cannabis (MADC), and which they interpret as indirect evidence of a male chromosome. Several other research groups have reported identification of male-associated markers using RAPD and AFLP . Ainsworth commented on these findings, stating that "It is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identified, markers for maleness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination."

Environmental sex determination is known to occur in a variety of species. Many researchers have suggested that sex in Cannabis is determined or strongly influenced by environmental factors . Ainsworth reviews that treatment with auxin and ethylene have feminizing effects, and that treatment with cytokinins and gibberellins have masculinizing effects. It has been reported that sex can be reversed in Cannabis using chemical treatment.

Aspects of cannabis production and use

• Medical cannabis discusses its use as a medication.
• Cannabis (drug) discusses its use as a recreational drug.
• Spiritual use of cannabis discusses sacramental and religious use.
• Hemp discusses its uses as a source of housing, oil, food, fibers, and industrial materials.
• Cannabis (drug) cultivation discusses aspects of cultivation for medicinal and recreational drug purposes
• Legal issues of cannabis focuses on the law and enforcement aspects of growing, transporting, selling and using cannabis as a drug.
  • Cannabis rescheduling in the United States
• Health issues and the effects of cannabis discusses the pharmacology, physical, and mental effects of Cannabis when used as drug.

Etymology

The plant name cannabis is of Semitic origin: ; However, the earlier Sumerian language used the word "kanubi", which means 'cane of two (sexes?)'. This is possibly the source for the Semitic usage.

The Biblical Hebrew term qěnēh bośem, literally "reed of balm", probably refers to cannabis according to some etymologists , but is more commonly thought to be lemon grass, calamus , or even sweet cane, due to widespread translation issues. The Hebrew Bible mentions it in Exodus 30:23 where God commands Moses to make a holy oil of myrrh, cinnamon, qěnēh bośem and cassia to anoint the Ark of the Covenant and the Tabernacle (and thus God's Temple in Jerusalem). Notably, this anointing oil is a special herbal formula that functions as a kind of polish and fragrance for the Ark and Tabernacle, and the Bible forbids its manufacture and use to anoint people (Exodus 30:31-33) with the exception of the Aaronic priesthood (Exodus 30:30)

Elsewhere, the Hebrew Bible simply uses "reed" qānēh as the name of a plant in four places whose context seems to mean "reed of balm" as a fragrant resin, Isaiah 43:24, Jeremiah 6:20, Ezekiel 27:19 and Song of Songs 4:14. The Hebrew name "reed of balm" comes from qěnēh (the noun construct form of qāneh) means a "reed" or "cane" and bośem means "balm" or "aromatic" resin. Hebrew may have adapted the name qannabbôs from "reed of balm" qěnēh bośem as a substitute for the ambiguous name "reed".

This Biblical Hebrew term is often mistranslated as "calamus", also called "lemon grass" (Cymbopogon citratus) or "sweet flag" (Acorus calamus), following an ancient misunderstanding in the Greek Septuagint translation. The Hebrew Bible was written across centuries well up to the 5th Century BCE. However, centuries later, by the time the Septuagint was written around the 2nd Century BCE, the archaic Hebrew word qěnēh bośem appears to have already abbreviated into the later Hebrew form qannabbôs, which is attested in Post Biblical Hebrew literature. Thus, the Septuagint did not recognize the Hebrew expression "reed of balm" and mistook it to refer to some unidentified plant. As a dynamic equivalent, the Septuagint rendered it as "calamus" (Greek kalamos), which indeed is a "balmy" (scented) reed. The calamus plant was known in Greek mythology and processed into an aphrodisiac.

Unambiguous Hebrew or Aramaic references to cannabis are rare and obscure. Syriac has qanpa (a loan from kannabis) and tanuma (see the Comprehensive Aramaic Lexicon.) but neither is found in the Peshitta, the Syriac Bible. Late Syriac Ahiqar texts include qanpa as "ropes of hemp" (tunbei de-qanpa). The Hebrew word qanbes, a loan word from kannabis, is used in the Mishnah as hemp in the sense of a constituent of clothing or other items.

The Scythian term cannabis probably derives from a Semitic origin as well. Sara Benetowa of the Institute of Anthropological Sciences in Warsaw is quoted in the Book of Grass as saying:

The astonishing resemblance between the Semitic kanbos and the Scythian cannabis lead me to suppose that the Scythian word was of Semitic origin. These etymological discussions run parallel to arguments drawn from history. The Iranian Scythians were probably related to the Medes, who were neighbors of the Semites and could easily have assimilated the word for hemp. The Semites could also have spread the word during their migrations through Asia Minor.

Likely, the name 'cannabis' was known from the Semitic merchants who sold this commodity throughout the ancient trade routes of Southeast Asia.

Comparing the English word hemp and the Greek word kannabis shows that the word came down from the presumed Proto-Indo-European language. Words like kanapish for "hemp" occur in some Finno-Ugrian languages. It is likely that, soon after agriculture started, hemp as a cultivated plant spread widely, carrying its name with it. Source of Rus. konoplja, Pers. kanab, Lith. kanapes "hemp," and Eng. canvas and hemp.

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See Also

Medical cannabis

Further reading

• Cannabis: A History (2005) Martin Booth ISBN 0-312-32220-8
• UNODC: World Drug Report 2006, Chapter 2: Cannabis: Why We Should Care (2006)

External links

• International Plant Names Index (IPNI)
• The Endocannabinoid System Network (ECSN) - Contains medical information to the Endocannabinoid System

Smoke weed wvery day- Snoop dogg

• Rosales
• Cannabis
• Herbs
• Fiber plants
• Underutilized crops
• Medicinal plants
• Psychedelics, dissociatives and deliriants