The availability of approximately 40 species of Gossypium offers the opportunity to develop an extensive array of cytoplasms in cultivated cottons. Vesta Meyer (Mississippi Agriculture and Forestry Experiment Station, Stoneville, MS) was the first to seriously attempt to transfer exotic cytoplasms into G. hirsutum. Through her efforts the following cytoplasms, in addition to the two cultivated species, are now available: G. tomentosum, G. arboreum, G. herbaceum, G. anomalum, G. longicalyx, an G. harknessii. The last of these is the current source of male sterility in cotton. Johnie Jenkins and coworkers (ARS, Starkville, MS) placed these cytoplasms into G. barbadense with the semigamy trait.