There are around thirty wild species and many hybrids developed in many areas, but the main species (diploid) are Gossypium herbaceum L. (var. typicum, or frutescens, or africanum), Gossypium arboreum L. (var. typicum, or neglectum, or cernuum).
The cultivated species (triploid) are Gossypium barbadense L, Gossypium hirsutum L., Gossypium religiosum L.
The origin is uncertain. The Herbaceum was imported as domesticated species to Saudi and Syria and then to India, where Arboreum has developed from the Herbaceum. Then it prevailed in Africa and Asia. From these species a triploid has developed which replaced the two other ones.
Many archaeological evidences show that cotton was domesticated several thousand years before our Era and in regions far apart: 10.000 BC in Egypt, Mexico 7000 BC, from 2300 BC in India. However, it seems certain that it is from India that it has spread to Persia in the 4th century BC and to Malaysia, Indonesia, Southeast Asia and China.
Gossypium arboreum is a perennial shrub up to 1.50m in height; other species can be perennial herbs or shrubs.
The colors of the flowers vary depending on the species, from off-white to purple. The fruits are ovoid capsules which open at maturity in 3 to 5 valves containing 6 to 12 seeds covered with hair, white fibers which can be 2 to 5 cm in length depending on the variety.
There are two types of fibers: long fibers (lints), and shorter hairs (linters).
The seeds, after removal of the fibers can produce oil. The roots are used as decoctions in the Indian pharmacopoeia for the treatment of urinary diseases.
The fibers used for textiles and paper production come from the hairs of the seeds of one or an other species.
In the case of paper, fibers tend to come from rags, they are rarely used raw. But in this case, the linters or more rarely, lints are used.
The first attempts to use fibers directly from the plant began in the early 20th century in the modern industry. Linters are torn by special gins. The lints are treated with caustic soda and linters by caustic solutions and are bleached.
