Jump to navigation Jump to search This article is about the plant genus. The number of bitcoin mining difficulty increase rate of metabolism within the genus is disputed. The plant is also known as hemp, although this term is often used to refer only to varieties of Cannabis cultivated for non-drug use. Cannabis has long been used for hemp fibre, for hemp oils, for medicinal purposes, and as a recreational drug.
Globally, in 2013, 60,400 kilograms of cannabis were produced legally. In 2014 there were an estimated 182. Cannabis growing as weeds at the foot of Dhaulagiri, Nepal. A thicket of wild cannabis in Islamabad, Pakistan. Cannabis is an annual, dioecious, flowering herb. As is common in serrated leaves, each serration has a central vein extending to its tip.
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. All known strains of Cannabis are wind-pollinated and the fruit is an achene. Many monoecious varieties have also been described, in which individual plants bear both male and female flowers. 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 flowers are used. 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. 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. The question of whether heteromorphic sex chromosomes are indeed present is most conveniently answered if such chromosomes were clearly visible in a karyotype. It is not surprising that male-associated markers are relatively abundant.