Hemp

Abstract

As well as providing a fibre of commercial importance, the hemp plant is the source of a narcotic drug, and the seeds are used for culinary purposes and as an animal feed. Oil extracted from the seed is a substitute for linseed oil in paint and varnish and is also used in soap-making. Like most plants of economic importance, hemp has frequently been studied by botanists. Its wide distribution, its varying form and its response to environment have been of special interest, and plant breeders have sought to develop strains suited to a particular climate or to the efficient production of one crop. Taxonomists have studied the plant and expressed many views about its affinities and its taxonomic position. It is now agreed that two genera, Cannabis and Humulus, form the family Cannabaceae and that Cannabis is a monotypic genus; Index Kewensis lists only the species C. sativa L., an erect dioecious annual which grows rapidly through a comparatively short growing season. A detailed botanical description of the species is given by Steam (1970).