Cotton is a tropical plant belonging to the mallow family. Its fibres surround the seeds inside the ripened fruits, or bolls, and these are spun into yarn for cloth. Other than flax, cotton is the oldest material to be used as a textile fibre. India, China, Egypt, Peru and Mexico all wore and used cotton as a textile fabric as far back as 7000 BC. Lancashire, with its damp atmosphere so useful to the spinning of cotton and its ready supply of water power and coal, became an important centre for cotton production from the 18th Century until the industry's decline in the post-war years.