208 



WILD AND CULTIVATED COTTONS 



Abrupt 

 changes. 



Choosing 

 of evi- 

 dence. 



Ancestral 

 types. 



leaves. From the remark on the attached label of the present 

 specimen it may be inferred that the American authorities were 

 induced to believe that, though widely different from King's Improved, 

 it was perhaps but a natural sport. 'Thousands of plants were 

 grown from the seed, and but very few reverted to the broad leaf 

 type.' 



Cook (' Weevil-Eesisting Adaptations of the Cotton Plant, 1906,' 

 p. 70) alludes to this oJcra as an ordinary example of ' abrupt changes 

 or sports; also called mutations, saltations, and discontinuous 

 variations. These are represented in cotton by the occasional 

 appearance of a plant with brown lint, deeply divided leaves (okra 

 cotton) or very short branches (cluster cotton).' In a foot-note he 

 continues : ' Some may be inclined to interpret these as reversions 

 and to argue that the deeply divided involucral leaves may be a 

 reminiscence of an ancestral character of the cotton.' Quite so : and 

 surely there is as great a danger in the conception of selective develop- 

 ment being carried to an unwarrantable extent, as in the theory of 

 hybridisation with its concomitant reversions (or recessive manifest- 

 ations) being over-done. The picking and choosing of evidence in 

 support of theories is ever a dangerous procedure. But there would 

 seem certain facts that cannot be neglected, such as the following : 

 no truly wild species has yet been discovered possessed of a pure 

 white fuzz and floss the undoubted wild forms have red or rust 

 coloured flosses. In neglected cultivation, red cottons constantly 

 appear with any and every known species of Gossypium, but imme- 

 diately these are placed under special cultivation, the coloured floss 

 disappears and the white one reappears. The red floss can hardly, 

 therefore, be other than an ancestral character. There is, moreover, 

 the geographical consideration. A group of undoubted wild species 

 exists in Central America, possessed of certain characteristics. From 

 that very country, as a matter of history, there have originated certain 

 cultivated stocks which show many close affinities to their associated 

 wild species. If selective development be made to alone account for 

 all this, then there very possibly is but one species of Gossypium in 

 the world. But how about the wild species are they all mere 

 climatological adaptations ? 



So again the fact that, when two or more forms of cotton are grown 

 side by side, crosses almost invariably occur (see hybrids of G. hir- 

 sutum, p. 193), which leads to the belief that their hybridisation might 

 almost be viewed as a case of opportunity rather than of suitability. 



