HYBRIDISATION 339 



tellapatti (often called the black-seeded jowari Jiathi) which can best 

 be accounted for by the belief that it is a naturally produced hybrid 

 between uppam and Bourbon cotton (see pp. 152-3). In the 

 remarks that follow regarding the pollen-grains of hybrid cottons, it Hybrids 

 will be seen that Professor Gammie of Poona, India, states that he of Asiatic 

 had actually produced hybrids between G. hirsutum and one of the can stocks, 

 many forms of G. obtusifolium (D x K hybrid No. 2) also between 

 G. hirsutum and G. roseum (VxD hybrid No. 3), thus proving that 

 hybrids between the so-called Asiatic and American cottons are not 

 only possible but actually exist (see remarks pp. 111-14). The 

 account (pp. 181-2) of Mr. Lawrence Ball's experiments at crossing 

 G. barbadense with G. punctatum, and the particulars afforded 

 (pp. 194, 234-5) regarding the production of the Long Staple Fertility 

 Uplands are also of the same nature. brid y ~ 



But, as already admitted, there would seem to be no doubt that 

 certain New World forms are difficult to hybridise with Old World 

 species. May not the explanation, however, be that they are them- 

 selves hybrids which in some instances might be expected to 

 resist further direct crossing? Moreover, it has been pointed out 

 (Section I. p. 62) that the genus Gossypium embraces several 

 species that probably may have to be transferred to other genera. 

 It is well known that many genera often have had species assigned 

 to them so remote from each other that they are often not capable 

 of direct hybridisation. And in the case of Gossypium, at all events, 

 there would almost appear to be occasional or accidental conditions 

 that favour hybridisation which, when not present, have given the 

 impression that crossing was impossible. In another place (p. 286) 

 I have incidentally alluded to some of the results obtained by Mr. W. 

 Austin Cannon in the hybridisation of cotton. His special studies on Spermato- 

 ' The Spermatogenesis of Hybrid Cotton ' (' Bull. Torrey Bot. Club,' 

 vol. 30, 1903, pp. 133-72, Plates 7 and 8) will be found of exceptional 

 interest and value. He not only gives a historic sketch of hybridisa- 

 tion but shows the special bearing of that science on cotton production. 

 His address to the New York Hybrid Conference of 1902 on some 

 ' Cytological Aspects of Hybrids,' forces attention on the question of 

 the relationship between cytological studies and the experimental 

 work of the hybridist. Mr. Cannon believes that (a) the normal Cyto- 

 divisions of the male nuclei lead to fertility while the abnormal 

 divisions conduce toward sterility. And (b) that the variation 

 of hybrids may or may not be associated with variation in 



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