Cotton
Family Malvaceae
Gossypium sp., cotton (Gos. sp 1), comprises a group of different species of annual or perennial shrub-like plants, dotted with oil glands, with variable leaves and characteristic large pentamerous flowers with numerous stamens, the lower parts of which are united into a tube. The fruit is a dry capsule, containing seeds, which are covered with unicellular hairs.
Distribution
Cotton is distributed in the tropical and subtropical regions of Africa, Asia, Australia and America.
Use
Cultivated cottons have 2 types of unicellular hairs growing from the epidermis of the seed: fuzz, in which the hairs are circular in cross section and cannot be spun; and lint, with longer hairs and a central cavity. On drying, the hair forms a twisted ribbon, which permits spinning. Wild cottons produce only fuzz.
In the Old World two lint-producing species occur: Gossypium herbaceum (Gos. sp 2), (Gos. sp 3) and Gossypium arboreum (Gos. sp 4). The first species is the first cotton cultivated in the Nile delta and was referred to as the ‘ wool bearing tree’ by Theophrastus in 350 BC. The second species was taken from India to East Africa in the 16th century and was grown by ancient Nubian people.
In the New World three different lint-producing species are of importance: Gossypium barbadense (= Gossypium peruvianum) (Gos. sp 5); Gossypium hirsutum (Gos. sp 6), (Gos. sp 7); and Gossypium tomentosum. The first two species are of Central and South American origin; the third one is endemic to the Hawaiian Islands. One variety of Gossypium hirsutum was taken from Mexico to the US about 1700 and became the ‘upland’ cotton, which developed a dominant place among the cottons. Varieties of Gossypium barbadense spread from South America and the Caribbean to West Africa and the Sudan. From this source the cotton in Egypt is derived.
Cotton lint is the most important fibre today (Gos. sp 9). It is woven into fabrics, either alone or in combination with other fibres. In India it is in use since early times (Gos. sp 10), (Gos. sp 11), but in many countries its use is of later date. Wool was the principle fibre of western and southern Europe; hemp (Cannabis sativa) (Ca sativa 1) in northern Europe; flax (Linum usitatissimum) (L. usitatissimum 1) in Egypt; and ramie (Boehmeria nivea) (B. nivea 1) in China. It was only after the invention of the saw gin and the development of the factory system that the rapid expansion of the use of cotton took place. Although the bulk of cotton is used for the manufacture of textile, it is also used in yarn, cordage, filter paper and bank notes. The seeds yield edible oil, which is used as cooking oil and in the manufacture of margarine, soap and lubricants. The residue is used as a protein-rich food for livestock. Fibres which were not removed from the seeds during ginning, are cut later and used in felt, mattresses, upholstery and carpets, and in chemical industries.
Except in the US, most cotton is picked by hand (Gos. sp 8). The average yield varies considerably, depending on the conditions, with the highest yield in California. Biggest producers are Russia, the US and China. Other important producing countries are India, Pakistan, Turkey, Brazil, Egypt, Mexico, Argentina, Sudan, and Iran.
Greatest exporters are the US, Egypt, Russia and Mexico. China produces entirely for internal use; India imports extra cotton. The greatest importing countries are Japan, Germany, France, England and Italy.