Cannabis News

• 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
• Legality 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
  • Drug policy of the Netherlands
• Health issues and the effects of cannabis discusses the pharmacology, physical, and mental effects of Cannabis when used as drug.

Although there are hundreds of strains of cannabis in existence, there are also many rumors and urban legends. Many alleged strains, such as Purple Haze, are very predominant in pop-culture (see right), but the actual existence of many of these strains is uncertain and the slang terms used to refer to these strains do not appear to be used by botanists. Some strains, such as G-13, are acknowledged to be urban legends.

Strains of cannabis:
* Acapulco gold
* BC Bud
* Cinderella 99
* Chocolate Thai
* Panama Red
* G-13
* Kush
* Northern Lights
* Purple Haze
* Quebec Gold
* White Widow

Some of the strains’ names, such as Chocolate Thai, popular in the early 1990s due to its supposed high potency, entered the mass culture. For example, Chocolate Thai was adopted as a stage name of a jazz performer, whose album The Real McCoy was released in 2006. It should be noted, however, that because there is no manufacturing or state control over the process of production of cannabis, many “strains” may in fact be just marketing brands adopted by drug dealers to increase sales.

Cannabis is predominantly dioecious, although many monoecious varieties have 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 that 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 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.

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 by K. Hirata in 1924 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 furthermore sex was strongly influenced by environmental conditions.

Since then, many different types of sex determination systems 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 1920s, 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”.
Dense raceme of carpellate flowers typical of drug-type varieties of Cannabis
Dense raceme of carpellate flowers typical of drug-type varieties of Cannabis

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. 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,

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. A PCR-based method for the detection of female-associated DNA polymorphisms by genotyping has been developed.

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). Recent phylogenetic studies based on cpDNA restriction site analysis and gene sequencing strongly suggest that the Cannabaceae arose from within the Celtidaceae clade, and that the two families should be merged to form a single monophyletic group.

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 Δ9-tetrahydrocannabinol (THC), but only THC is psychoactive. Since the early 1970s, 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.
Top of Cannabis plant in vegetative growth stage.
Top of Cannabis plant in vegetative growth stage.

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. However, physical barriers to gene exchange (such as the Himalayan mountain range) might have enabled Cannabis gene pools to diverge before the onset of human intervention, resulting in speciation. 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.

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 occurring on separate plants, although hermaphroditic plants 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, though these are referred to as ‘intersexual’ or hermaphroditic rather than monoecious, since staminate and pistillate structures appear at different points on the plant, not within the same flower.

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

All known 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. 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 (marijuana), resin (hashish), or various extracts collectively known as hashish oil. In the early 20th century, it became illegal in most of the world to cultivate or possess Cannabis for drug purposes.

The plant name cannabis is from Greek κάνναβις (kánnabis), via Latin cannabis, originally a Scythian or Thracian word, also loaned into Persian as kanab. English hemp (Old English hænep) may be an early loan (predating Grimm’s Law) from the same source. In Hebrew the word is קַנַּבּוֹס [qan:a'bos].

The further origin of the Scythian term is uncertain, although it is possible that it traces back to the Assyrian word ‘qunubu’ (way to produce smoke) which was used to refer to the plant.

Cannabis (Cán-na-bis) is a genus of flowering plants that includes three putative species, Cannabis sativa L., Cannabis indica Lam., and Cannabis ruderalis Janisch. These three taxa are indigenous to central Asia and surrounding regions. Cannabis has long been used for fibre (hemp), for medicinal purposes, and as a psychoactive. Industrial hemp products are made from Cannabis plants selected to produce an abundance of fiber and minimal levels of THC (Δ9- tetrahydrocannabinol), one psychoactive molecule that produces the “high” associated with marijuana. The drug consists of dried flowers and leaves of plants selected to produce high levels of THC. Various extracts including hashish and hash oil are also produced.[1] The cultivation and possession of Cannabis for recreational use is outlawed in most countries.