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{{otheruses4|the plant genus ''Cannabis''|use as a psychoactive drug|Cannabis (drug)|use as a therapeutic drug|Medical Cannabis|non-drug cultivation and uses|Hemp}}
{{Taxobox
| color = lightgreen
| name = Cannabis
| image = Cannabis sativa Koehler drawing.jpg
| image_width = 250px
| image_caption = common hemp
| regnum = ]ae
| divisio = ]
| classis = ]
| ordo = ]
| familia = ]
| genus = '''''Cannabis'''''
| genus_authority = ]
| subdivision_ranks = Species
| subdivision =
]<br />
]<br />
]
}}

'''''Cannabis''''' ('']'') is a genus of ]s that includes three putative species, ''Cannabis sativa'' L., ''Cannabis indica'' Lam., and ''Cannabis ruderalis'' Janisch. These three taxa are indigenous to ] and surrounding regions. Industrial ] products are made from ''Cannabis'' plants selected to produce an abundance of fiber and minimal levels of ] (Δ<sup>9</sup>- tetrahydrocannabinol), one ] molecule that produces the "high" associated with ]. The drug consists of dried flowers and leaves of plants selected to produce high levels of THC. Various extracts including ] and hash oil are also produced.<ref name=erowid>Erowid. 2006. . Retrieved on 25 Feb 2007</ref> The cultivation and possession of ''Cannabis'' for recreational use is outlawed in most countries.

== Etymology ==
{{main|Cannabis (etymology)}}
The plant name '''cannabis''' is from ] '''{{lang|grc|κάνναβις}}''' (''{{lang|grc|kánnabis}}''), via ] ''{{lang|la|cannabis}}'', originally a ] or ] word, also loaned into ] as ''{{lang|fa|kanab}}''. English '']'' (Old English {{lang|ags|hænep}}) may be an early loan (predating ]) from the same source.

The further origin of the Scythian term is uncertain. It may be of ] origin, ] '''קַנַּבּוֹס''' (qannabbôs).

== Description ==
''Cannabis'' is an ], ], ] ]. The ] are ], with ] ]s. 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 ] and the upper leaf pairs in an alternate arrangement on the main stem of a mature plant.

''Cannabis'' usually has ] ] with ] "male" and ]late "female" flowers occurring on separate plants,<ref name=”lebel1997”>Lebel-Hardenack, S. and S. R. Grant. 1997. Genetics of sex determination in flowering plants. ''Trends in Plant Science'' '''2'''(4): 130–136.</ref> although ] flowers sometimes occur.<ref name="moliterni2005">Cristiana Moliterni, V. M., L. Cattivelli, P. Ranalli. and G. Mandolino. 2005. . ''Euphytica'' '''140'''(1-2): 95-106. Retrieved on 25 Feb 2007</ref> Male flowers are borne on loose ]s, and female flowers are borne on ]s.<ref name="bouquet1950"> Bouquet, R. J. 1950. . United Nations Office on Drugs and Crime. Retrieved on 23 Feb 2007</ref> It is not unusual for individual plants to bear both male and female flowers in some strains, a condition called monoecy.<ref name="mignoni1999">Mignoni, G. 1999. . United Nations Office on Drugs and Crime. Retrieved on 5 Oct 2006</ref> On ] plants, flowers of both sexes may occur on separate ]s, or on the same inflorescence.<ref name="moliterni2005"/>

], ], and other volatile compounds are secreted by glandular ] that occur most abundantly on the floral ]es and ]s of female plants.<ref name="mahlberg2001a">Mahlberg, Paul G. and Eun Soo Kim. 2001. . ''The Hemp Report'' '''3'''(17). Retrieved on 23 Feb 2007</ref>

All known strains of ''Cannabis'' are ]<ref name="clarke1991a">Clarke, Robert C. 1991. ''Marijuana Botany'', 2nd ed. Ron Publishing, California. ISBN 0-914171-78-X</ref> and produce "]s" that are technically called ]s.<ref name="small1975c">Small, E. 1975. Morphological variation of achenes of ''Cannabis''. ''Canadian Journal of Botany'' '''53'''(10): 978-987.</ref> Most strains of ''Cannabis'' are ]s,<ref name=clarke1991a/> with the possible exception of ''C. sativa'' subsp. ''sativa'' var. ''spontanea'' (= ''C. ruderalis''), which is commonly described as "auto-flowering" and may be ].

''Cannabis'' is naturally ], having a ] complement of 2n=20, although polyploid individuals have been artificially produced.<ref name=”small1972a”>Small, E. 1972. Interfertility and chromosomal uniformity in ''Cannabis''. ''Canadian Journal of Botany'' '''50'''(9): 1947-1949.</ref>
Cannabis is a genus of flowering plant which includes one or more species. The plant is believed to have originated in the mountainous regions just north west of the Himalayas. It is also known as hemp, although this term usually refers to varieties of Cannabis cultivated for non-drug use. Cannabis plants produce a group of chemicals called cannabinoids which produce mental and physical effects when consumed. As a drug it usually comes in the form of dried buds or flowers(]), ] (]), or various extracts collectively known as ].<ref name=erowid/> In the early 20th century, it became illegal in most of the world to cultivate or possess Cannabis for drug purposes.

== Reproduction ==
=== Breeding systems ===
]
''Cannabis'' is predominantly ],<ref name=clarke1991a/><ref name="ainsworth2000">Ainsworth, C. 2000. . ''Annals of Botany'' '''86'''(2): 211-221. Retrieved on 24 Feb 2007</ref> although many monoecious varieties have been described.<ref name="meijer1999a">de Meijer, E. P. M. 1999. ''Cannabis'' germplasm resources. In: Ranalli P. (ed.). ''Advances in Hemp Research'', Haworth Press, Binghamton, NY, pp. 131-151. ISBN 1-56022-872-5</ref> Subdioecy (the occurrence of monoecious individuals and dioecious individuals within the same population) is widespread.<ref name="mignoni1999"/><ref name="schumann1999">Schumann, E., A. Peil, and W. E. Weber. 1999. . ''Genetic Resources and Crop Evolution'' '''46'''(4): 399-407. Retrieved on 24 Feb 2007</ref><ref name="ranalli2004a">Ranalli, P. 2004. Current status and future scenarios of hemp breeding. ''Euphytica'' '''140'''(1): 121-131.</ref> Many populations have been described as sexually labile.<ref name="hirata1924">Hirata, K. 1924. Sex reversal in hemp. ''Journal of the Society of Agriculture and Forestry'' '''16''': 145-168.</ref><ref name="schaffner1931">Schaffner, J. H. 1931. The fluctuation curve of sex reversal in staminate hemp plants induced by photoperiodicity. ''American Journal of Botany'' '''18'''(6): 424-430.</ref><ref name="mandolino2002a"/>

As a result of intensive selection in cultivation, ''Cannabis'' exhibits many sexual phenotypes that can be described in terms of the ratio of female to male flowers occurring in the individual, or typical in the cultivar.<ref name="truta2002a">Truta, E., E. Gille, E. Toth, and M. Maniu. 2002. . ''Journal of Applied Genetics'' '''43'''(4): 451-462. Retrieved on 24 Feb 2007</ref> Dioecious varieties are preferred for drug production, where the ] are preferred. Dioecious varieties are also preferred for textile fiber production, whereas monoecious 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.<ref name="mignoni1999"/>

=== Mechanisms of sex determination ===

''Cannabis'' has been described as having one of the most complicated mechanisms of ] among the dioecious plants.<ref name="truta2002a"/> Many models have been proposed to explain sex determination in ''Cannabis''.

Based on studies of sex reversal in ], it was first reported by K. Hirata in 1924 that an ] is present.<ref name="hirata1924"/> At the time, the XY system was the only known system of sex determination. The ] was first described in Drosophila spp in 1925.<ref name=”bridges1925”>Bridges, C. B. 1925. Sex in relation to chromosomes and genes. ''American Naturalist'' '''59''': 127-137.</ref> Soon thereafter, Schaffner disputed Hirata's interpretation,<ref name="schaffner1929">Schaffner, J. H. 1929. Heredity and sex. ''Ohio Journal of Science'' '''29'''(1): 289-300.</ref> and published results from his own studies of sex reversal in hemp, concluding that an X:A system was in use and that furthermore sex was strongly influenced by environmental conditions.<ref name="schaffner1931"/>

Since then, many different types of sex determination systems have been discovered, particularly in plants.<ref name="ainsworth2000"/> 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.<ref name=”negrutiu2001”> Negrutiu, I., B. Vyskot, N. Barbacar, S. Georgiev, and F. Moneger. 2001. . ''Plant Physiology'' '''127'''(4): 418-424.</ref>

Since the 1920s, a number of sex determination models have been proposed for ''Cannabis''. Ainsworth<ref name="ainsworth2000"/> 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 ]. ''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 ]). 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.<ref name="menzel1964">Menzel, Margaret Y. 1964. Meiotic chromosomes of monoecious Kentucky hemp (''Cannabis sativa''). ''Bulletin of the Torrey Botanical Club'' '''91'''(3): 193-205.</ref> According to other researchers, no modern karyotype of ''Cannabis'' had been published as of 1996.<ref name=”hong1996a”>Shao Hong and Robert C. Clarke. 1996. . ''Journal of the International Hemp Association'' '''3'''(2): 55-60. Retrieved on 25 Feb 2007</ref> Proponents of the XY system state that Y chromosome is slightly larger than the X, but difficult to differentiate cytologically.<ref name="peil2003">Peil, A., H. Flachowsky, E. Schumann, and W. E. Weber. 2003. Sex-linked AFLP markers indicate a pseudoautosomal region in hemp (''Cannabis sativa'' L.). ''Theoretical and Applied Genetics'' '''107'''(1): 102-109.</ref>

More recently, Sakamoto and various co-authors<ref name=”sakamoto1995a”> Sakamoto, K., K. Shimomura, Y. Komeda, H. Kamada, and S. Satoh. 1995. ''Plant & Cell Physiology'' '''36'''(8): 1549-1554. Retrieved on 25 Feb 2007</ref><ref name=”sakamoto2005a”> Sakamoto, K., T. Abe, T. Matsuyama, S. Yoshida, N. Ohmido, K. Fukui, and S. Satoh. 2005. ''Genome'' '''48'''(5): 931-936. Retrieved on 25 Feb 2007</ref> have used ] to isolate several ] 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 ].<ref name="torjek2002">Törjék, O., N. Bucherna, E. Kiss, H. Homoki, Z. Finta-Korpelová, I. Bócsa, I. Nagy, and L. E. Heszky. 2002. Novel male specific molecular markers (MADC5, MADC6) for sex identification in hemp. ''Euphytica'' '''127''': 209-218.</ref><ref name="mandolino2002a">Mandolino, Giuseppe and Paolo Ranalli. 2002. . ''Journal of Industrial Hemp'' '''7'''(1): 7-23. Retrieved on 23 Feb 2007</ref><ref name="meijer2003a">Meijer, Etienne P. M. de, M. Bagatta, A. Carboni, P. Crucitti, V. M. Cristiana Moliterni, P. Ranalli, and G. Mandolino. 2003. ''Genetics'' '''163'''(1): 335-346. Retrieved on 23 Feb 2007</ref> 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."<ref name="ainsworth2000" />

Environmental sex determination is known to occur in a variety of species.<ref name=”tanurdzic2004”>Tanurdzic, M. and J. A. Banks. 2004. Sex-determining mechanisms in land plants. ''Plant Cell'' '''16''' (suppl.): S61-71.</ref> Many researchers have suggested that sex in ''Cannabis'' is determined or strongly influenced by environmental factors.<ref name=schaffner1931/> Ainsworth reviews that treatment with ] and ] have feminizing effects, and that treatment with ] and ] have masculinizing effects.<ref name=ainsworth2000/> It has been reported that sex can be reversed in ''Cannabis'' using chemical treatment.<ref name=”mohanram1982”>Mohan Ram, H. Y., and R. Sett. 1982. Induction of fertile male flowers in genetically female ''Cannabis sativa'' plants by silver nitrate and silver thiosulfate anionic complex. ''Theoretical and Applied Genetics'' '''62''': 369-375.</ref>
A ]-based method for the detection of female-associated ] by ] has been developed.<ref name=PCR>Journal of Industrial Hemp 2003 Vol 8 issue 1 page 5-9, Female-Associated DNA Polymorphisms of Hemp (''Cannabis sativa'' L.), Hong Shao, Shu-Juan Song, Robert C. Clarke </ref>

== Aspects of ''Cannabis'' production and use ==
]

*] discusses its use as a medication.
*] discusses its use as a recreational ].
*] discusses sacramental and religious use.
*] discusses its uses as a source of ], ], ], ], and industrial materials.
*] discusses aspects of cultivation for medicinal and recreational drug purposes
*] focuses on the law and enforcement aspects of growing, transporting, selling and using cannabis as a drug.
**]
**]
*] discusses the ], physical, and mental effects of ''Cannabis'' when used as drug.

==Gallery of images==
<gallery>
Image:Cannabis_sativa1.JPG|Cannabis plants
Image:Cannabis_sativa2.JPG|Cannabis plants
Image:Cannabis_sativa3.JPG|Cannabis plants
Image:Cannabis_sativa4.JPG|Cannabis plants
</gallery>

== References ==
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== See also==
*]
*]
*]
{{Ancient anaesthesia-footer}}
{{Herbs & spices}}
{{Cannabis resources}}

== Further reading ==
* ''Cannabis: A History'' (2005) Martin Booth ISBN 0-312-32220-8
*
*

== External links ==
{{Portal}}
{{wiktionary}}
{{Wikispecies|Cannabis}}
{{commons|Cannabis sativa}}
{{wikiquote|Cannabis}}
*
* - Contains medical information to the Endocannabinoid System

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Revision as of 13:03, 7 November 2007