208 Studies in Indian Cotton 



same generation. Such crossing is confined to individual plants of the 

 same pure line and its success is of some interest in view of the facts 

 noted by Darwin (5)\ Where the produce by self-fertilisation is required, 

 as in the F^ and subsequent generations, the flower is invariably pro- 

 tected in spite of the considerable labour of handling some 9000 flowers 

 in the course of four to six weeks. In no case has the produce of an 

 unprotected flower been included in the results given below. 



The genus Gossypium and the types used in the 

 investigations. 



For reasons which will appear in the course of this paper the author 

 does not consider it advisable at the present time to put forward any 

 scheme of classification to which reference can be made for identifica- 

 tion of the types handled by him. Nor is he able to accept in full any 

 of the classifications hitherto advanced. Only those types to which 

 reference is made are therefore briefly described and referred to their 

 place in the schemes in current use. The oldest of these are the 

 classical studies of the genus Gossypium by Todaro and Parlatore (15 

 and 14) where comprehensive schemes for the classification of the genus 

 are to be found. At a more recent date The Indian Cottons have been 

 dealt with by Gammie (9) and lastly Watt has reviewed the whole genus 

 in full detail in his Wild and Cultivated Cottons of the World (20). 



The Indian cottons fall into two marked groups distinguished from 

 each other by the type of secondary branching. Arising from the main 

 axis, which is invariably a monopodium, the secondary branches may 

 either be monopodia or sympodia. The type in which all the secondary 

 branches are sympodia has not been observed though it frequently 

 happens that individual plants of certain types exhibit sympodial 

 secondary branching only (cf. PI. XXXIV, facing p. 208). 



Nevertheless, in pure races, the number of monopodia produced at 

 the base of a sympodial type is invariably limited and the two groups 

 stand in obvious contrast on this point. 



Monopodial branches are in most cases, though not invariably, 

 ascending while the sympodial branches are usually spreading and the 

 two groups lie in marked contrast to the eye. This difl'erence appears 

 to be fundamental and not limited to the appearance. The flowers are 

 invariably borne on sympodia which take the form of leafy cymes or, 

 more strictly, monochasia. In the sympodial group, therefore, the 

 1 See also Goebel, K. in Darwinism and Modem Science, p. 401. 



