Cotton is a soft, fluffy staple fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....

 that grows in a boll, or protective capsule, around the seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s of cotton plants of the genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

Gossypium is the cotton genus. It belongs to the tribe Gossypieae, in the mallow family, Malvaceae, native to the tropical and subtropical regions from both the Old and New World. The genus Gossypium comprises around 50 species , making it the largest in species number in the tribe Gosssypioieae....

. The fiber is almost pure cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

. The botanical purpose of cotton fiber is to aid in seed dispersal.

The plant is a shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 native to tropical and subtropical regions around the world, including the Americas, Africa, and India. The greatest diversity of wild cotton species is found in Mexico, followed by Australia and Africa.