Native Hawaiian cotton (Gossypium tomentosum Nutt

mentosum Nutt., is one of the more common of the few endemic species which still survive on the coastal plains of the Hawaiian Islands, it remains relatively unknown to the geneticist. Elsewhere it has been grown with indifferent success in experimental culture. Under such di-verse conditions as those found in the West Indies, southern Mexico, the U. S. cotton belt, and in greenhouse culture, it flowers sparingly and even less frequently sets seeds. As a con-sequence, experimental studies have been very restricted, and cytogenetic analysis has been con-fined almost entirely to the few crosses which have been made with annual forms of the related New World species, G. barbadense L. and G. hirsutum L. To the technical difficulties may be added the lack of representative collec-tions of the species in culture. The few accessions studied have usually been obtained from the more readily available Oahu populations, and less frequently from Molokai. These have been supplied to cotton geneticistsrhrough the cour-tesy of resident Hawaiian botanists, J. F. Rock, O. Degener, A. Mangelsdorf, and others, and patiently resupplied as fast as the stocks in culture expired. As seen in culture, the different accessions ' show little morphological variation (finely to-mentose vegetative parts, sulphur-yellow and spotless flowers, long anther filaments partly fused in pairs, nectariless leaves, and undifferen-tiated seed fibers). More recently, visitors to the islands, unacquainted with the taxonomy of the species, have sent seed samples to the mainland, and the plants grown from some of these appear to differ rather widely from earlier "authentic" accessions. It has long been recognized that an under-standing of the degree of relationship existing between G. tomentosum and the other 52