Gossypium
…America and Pacific islands are tetraploid, apparently due to a single hybridization event around 1.5 to 2 million years ago. The tetraploid species are G. hirsutum, G. tomentosum, G. mustelinum, G. barbadense, and G. darwinii. Cultivated cottons are perennial shrubs, most often grown as annuals. Plants are 1–2 m…