In 1937, the Marijuana Tax Act put cannabis under the regulation of the Drug Enforcement Agency, criminalizing possession of the plant throughout the country. After 24 hours to a few days, minuscule psychoactive effects may be felt, depending on dosage, frequency and tolerance to the drug. At the top of a flowering plant, this number again diminishes to a single leaflet per leaf. Normal cognition is restored after approximately three hours for larger doses via a smoking pipe, bong or vaporizer. Secondary psychoactive effects, such as a facility for philosophical thinking, introspection and metacognition have been reported among cases of anxiety and paranoia. It is important to distinguish between the two familiar subspecies of the cannabis plant, Warf said marijuana dating. The plant was first outlawed in Utah in 1915, and by 1931 it was illegal in 29 states, according to the report.  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.  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. Industrial hemp products are made from cannabis plants selected to produce an abundance of fiber. , and some of the tombs of noble people buried in Xinjiang region of China and Siberia around 2500 B.  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.
 Hillig concluded that the patterns of genetic, morphological, and chemotaxonomic variation support recognition of C marijuana dating. Heterosomes were not observed in analyzed individuals of monoecious Kentucky hemp, nor in an unidentified German cultivar. Cannabis aficionados recognize three distinct types based on such factors as morphology, native range, aroma, and subjective psychoactive characteristics.  However, if a large amount is taken orally the effects may last much longer. The history of cannabis use goes back as far as 12,000 years, which places the plant among humanity s oldest cultivated crops, according to information in the book Marihuana: The First Twelve Thousand Years (Springer, 1980). Mexicans were frequently blamed for smoking marijuana, property crimes, seducing children and engaging in murderous sprees. For the most part, it was widely used for medicine and spiritual purposes, during pre-modern times, said Warf, a professor of geography at the University of Kansas in Lawrence. (The L was included in the name in honor of the botanist Carl Linnaeus. In September 2005, New Scientist reported that researchers at the Canberra Institute of Technology had identified a new type of Cannabis based on analysis of mitochondrial and chloroplast DNA. ] This map shows how marijuana spread throughout the world, from its origins on the steppes of Central Asia. However, the serration vein originates from lower down the central vein of the leaflet, typically opposite to the position of, not the first notch down, but the next notch. Dioecious Kentucky hemp was assumed to use an XY mechanism.
Marijuana has been legal in many regions of the world for most of its history. Ruderalis is the informal name for the short plants that grow wild in Europe and central Asia. Primary psychoactive effects include a state of relaxation, and to a lesser degree, euphoria from its main psychoactive compound, tetrahydrocannabinol..  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. ) This subspecies is known as hemp; it is a nonpsychoactive form of cannabis, and is used in manufacturing products such as oil, cloth and fuel. have included large quantities of mummified psychoactive marijuana.  He considered the genus to be monotypic, having just a single species that he named Cannabis sativa L. An international team demonstrated that this material contained tetrahydrocannabinol, the psychoactive component of cannabis. The cannabis was presumably employed by this culture as a medicinal or psychoactive agent, or an aid to divination. Over the next centuries, cannabis migrated to various regions of the world, traveling through Africa, reaching South America in the 19th century and being carried north afterwards, eventually reaching North America.  This percentage has not changed significantly between 1998 and 2014. It arrived in the southwest United States from Mexico, with immigrants fleeing that country during the Mexican Revolution of 1910-1911.
For other uses, see Cannabis (disambiguation). .