COTTON. Gossypium. Malvacece. Figs. 354-367.
The cotton of commerce is the hair or fiber on seeds of plants belonging to the genus Gossypium, a mem ber of the Mallow family. This genus is distinguished from the other genera of the family by the presence of three to five bracts surrounding the flowers, and by the seed being covered with wool. Many attempts have been made to classify and limit the species of Gossypium, but so far the authorities have failed to agree. The great variability and tendency to hybridize make it very difficult to determine to what species a given plant may belong. However, it is commonly conceded that there are only a few spe cies whose products enter into commerce, and that the bulk of the production is from two species, namely, G. hirsutum, which furnishes the upland cottons (Figs. 101, 355, 356, 357), and G. Barba dense, the source of the sea-island and Egyptian cottons (Figs. 100, 356, 357). The ordinary upland cotton in American literature has been commonly referred to as G. herbaceunt, but after a careful study of types Mr. L. H. Dewey, of the United States Department of Agriculture, has concluded that this is an error and that our upland cotton, which is apparently derived from a wild Mexican variety, is G. hirsutum. In the United States G. hirsutum and G. Barbadense are the only two species that are cultivated commercially. The crop of India, which, aside from that of the United States, is the largest produced by any country, is probably derived principally from varieties of G. herbaceum, while the Egyptian crop is produced by varieties which are supposed to belong to the species G. Bar badense. Tho Egyptian cotton varieties resemble sea-island cotton very closely in all of their prin cipal characters aside from the lint, which in some of the varieties, such as Mit-afifi and Ashmouni, is light brown and rather coarse and crinkly.
All cultivated species are perennial in climates without frost, but in cultivation they are usually treated as annuals. The plants are mostly shrubby, more or less branching and two to ten feet high. The roots consist of several laterals, and a tap root which penetrates the soil to a considerable depth. The limbs of sea-island are smooth, while those of upland are covered with delicate, whitish hairs. The leaves are three- to five-lobed — sea
island usually having three and the upland five. The flowers are perfect and resemble the holly hock or When newly open they are large and white in upland, turning red with age, and creamy yellow in sea-island, with a purple spot at the base of each petal. They are surrounded by three to five fringed or deeply cut bracts form ing the "squares"—the number corresponding to the number of cells in the bolls or pods. These bracts are much larger and the indentations are deeper and more numerous in sea-island than in upland varieties. Stamens are many, united in a tube about the single compound pistil; stigmas three to five. The fruit consists of three- to five-celled capsules or "bolls" which burst open at maturity through the middle of the cells, each cell liberating seven to ten seeds covered with long fibers. The fiber is a tubular hair-like cell to to of an inch in diameter, somewhat flattened, and spirally twisted. It is this latter character which gives the cotton its spinning qualities. The length, tenacity and fineness of the fibers determines the value of the cotton. Sea-island excels upland in these respects and therefore commands a much better price. Sea island cotton seeds are small, black and smooth, while, as a rule, upland seeds are larger, and, after the fiber is removed, are covered with a dense whit ish or greenish fuzz. The bolls of sea-island rarely contain more than three cells, while those of up land usually have four and sometimes five. Sea-island bolls are much smaller and more pointed than upland.
There are many com mercial varieties i n each of the above spe cies which have never been classified botani cally, and whose true history will probably never be known. It is very difficult to classify them, owing to the readiness with which they are cross-fertilized and the great range of variation of the individual plants in a given variety. Some of them possess characters which suggest that they are produced by the hybridization of sea-island and upland varieties, while many seem to be the products of natural variation and selection.