Cotton is the seed fiber of Gossypium in Malvaceae, which is native to the subtropical zone. The plant is shrubby and can grow to 6 meters high in tropical areas, generally 1 to 2 meters high.

The flower is milky white, turns dark red soon after flowering and then withers, leaving a small green capsule called cotton boll. There are cottonseeds in the cotton boll. The hairs on the cottonseeds grow from the surface of the cottonseeds and fill the inside of the cotton bolls. When the cotton bolls are mature, they crack and expose soft fibers. The fiber is white or white with yellow, about 2-4 cm (0.75-1.5 inch) long, containing about 87-90% cellulose, 5-8% water and 4-6% other substances. The countries with the highest cotton production include China, the United States, India, etc.

The origin of cotton is India and Arabia. Before cotton was introduced into China, China had only kapok for filling pillows and mattresses, but no cotton for weaving. Before the Song Dynasty, China had only the word "mian" next to silk, not the word "mian" next to wood. The word "mian" began to appear in the book of song. It can be seen that cotton was introduced at the latest in the northern and Southern Dynasties, but it was mostly planted in the border areas. A large number of cotton were introduced into the mainland. At the end of the Song Dynasty and the beginning of the Yuan Dynasty, the record of cotton introduction into China said: "cotton was first introduced into China between the song and Yuan Dynasties, and Guanshan, Fujian and Guangdong first gained its benefits. It was covered by the foreign countries, Fujian and Guangdong were connected with ships, and Guanshan, Shaanxi and western regions."

From then on, we can understand that cotton was introduced by land and sea. Quanzhou's cotton was introduced by sea and soon spread in the south. As for the nationwide promotion of cotton, it was not until the early Ming Dynasty that Zhu Yuanzhang pushed it out by force.

Cotton is an annual herb, 0.6-1.5 meters high. The twigs are sparsely hairy. The leaves are broad ovate, 5-12 cm in diameter. The length and width are nearly the same or relatively wide. The base is cordate or heart-shaped truncated, often 3-lobed, rarely 5-lobed. The middle lobe is often deeply split to half of the leaf. The lobes are wide triangular ovate, the apex is gradually pointed, the base is wide, the upper part is nearly glabrous, and is covered with coarse hairs along the veins, and the lower part is sparsely villous; Petiole 3-14 cm long, sparsely pilose; Stipules ovate falcate, 5-8 mm long, caducous.

Cotton is solitary in leaf axils, and the pedicel is usually slightly shorter than the petiole; Bracteoles 3, detached, heart-shaped at the base, with 1 gland, 7-9 teeth at the edge, 4 cm long and 2.5 cm wide, covered with bristles and cilia; Calyx cup-shaped, lobes 5, triangular, ciliate; The flowers are white or light yellow, then turn pale red or purple, 2.5-3 cm long; The stamen column is 1.2 cm long.

Capsule ovoid, 3.5-5 cm long, beaked, 3-4-loculed; The seeds are separated, oval, with white long cotton wool and gray short cotton wool that is not easy to peel. The flowering period is summer and autumn.