Marijuana (Cannabis sativa) is an annual herbaceous plant in the Cannabis genus, a species of the Cannabaceae family. The leaves are palmately compound or digitate, with serrate leaflets. The first pair of leaves usually have a single leaflet, the number gradually increasing up to a maximum of 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 leaves are opposite, ovate to lanceolate, and have petioles up to 2 cm long. The upper leaves are alternate and lack a stalk. All leaves have saw-toothed edges. The flowers are small and greenish-white, with each having four petals arranged in two opposing pairs. As is typical in serrated leaves, each serration has a central vein extending to its tip.
The fruit is an achene. Most varieties of Cannabis require 60–90 days flowering time if grown outdoors, although indoor growers employing artificial lighting may finish sooner than this due to the photo period being extended by several hours at night. It can be harvested all year round indoors. Plants grown outdoors typically flower between late spring and mid-fall while those grown indoors produce year-round as long as light exposure remains adequate (12 hours daily).
Marijuana has been used for medicinal purposes for thousands of years. In ancient China it was used as a treatment for various diseases such as gout and malaria. In medieval Europe it was prescribed for leprosy, while in India it was used to relieve pain and increase appetite during convalescence from tuberculosis. Modern medicine makes use of marijuana’s antiemetic properties in cancer chemotherapy,”