Treated American Upland Cotton Seeds. Non-GMO. Heirloom. Annual or Perennial. Gossypium hirsutum. AKA: Upland Cotton or Mexican Cotton. 145-160 days. American Upland is the most popular variety of cotton in the world as nearly all commercially produced cotton is a cultivar of American Upland. Upland cotton seed is widely known as Mexican cotton for its ability to thrive in warm, arid, and full sun climates with poor soils, and are known to suffer from too much care. About 250 cotton seeds per Ounce.