packed than flowers on the male plants. Flowering is induced by lengthening dark periods to 11-13 hours to simulate the end of summer and the beginning of autumn (UNODC 2006).

Throughout human history, cannabis has been used for textiles, paper, medicine, and food (Abel 1980). It was originally native to central Asia and historically was cultivated in China, the rest of Asia, and Europe. It has become more widespread, growing in temperate, tropical, and subarctic climates (Duke 1983). Most botanists consider cannabis as a single species, Cannabis sativa, but some (see McPartland and West 1999) consider C. sativa as one of three species in the Cannabaceae family that is used to produce marijuana.

Cultivars of C.sativa that grow more than 6 m in height produce a durable fiber called hemp. The production of hemp predates written history and is thought to have begun in China. Early Chinese texts indicate that hemp was cultivated to make cloth, the stalks were used as fuel, and the seeds were used for oil and food. In the present report, cannabis refers to the plant species, hemp refers to industrial hemp, and marijuana refers to the psychotropic drug (recreational or medical).

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FIGURE 3-1 Cannabis sativa. Source: Richard A. Howard Image Collection, courtesy of Smithsonian Institution.



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