Cotton, seed fiber of Malvaceae, is native to subtropics. The plant is shrubby and can grow to 6 meters high in tropical areas, usually 1 to 2 meters. The flowers are milky white, turn dark red shortly after flowering, and then wither, leaving a small green capsule called cotton boll. There are cottonseed in the cotton boll, and the fluff on the cottonseed grows from cottonseed hulls and fills the inside of the cotton boll. When the cotton boll matures, it splits, revealing soft fibers. The fiber is white or yellowish white, about 2 ~ 4cm long, and contains about 87 ~ 90% cellulose. The countries with the highest cotton production are China, the United States and India.