142 THE COTTON PLANT IN EGYPT CHAP. 



In F 2 we found, by simple matching, that 48 plants 

 had stipules like the Ann, 59 like the Sultani, while 27 

 were recorded as doubtful. 



The evidence is inconclusive, but it again points to 

 some slight complexity, possibly a ratio of 9 : 7. 



The surface and glandulation of the boll. All 

 parts of the cotton plant, other than the root, contain 

 abundant resin glands, which produce the characteristic 

 black speckling externally. The depth at which these 

 glands are situated in the ovary wall is characteristic of 

 different kinds of cotton plants. In most Egyptian bolls 

 they are near the epidermis, which is depressed above 

 them, forming small craters. In American Uplands we 

 find the glands situated much further below the epidermis, 

 which is not depressed, so that the surface of the boll is 

 smooth, and the speckling is scarcely visible. The F 1 of 

 these two forms is intermediate, though more like the 

 Egyptian parent. 



A large number of bolls have been pickled and sectioned 

 in the attempt to understand the inheritance of this 

 character. It appears to be straightforward, but the 

 evidence is not convincing. The appearance of the surface 

 is not solely dependent on the glandulation ; Egyptian 

 bolls are bright green and shiny, while Upland bolls are of 

 a dull, grey-green colour. Some structural differences are 

 also shown by the microscope. 



Thus the fact that an F 2 was matched into 17 Uplands : 

 33 F! type : 14 Egyptian type, must not be taken as 

 evidence of simple segregation. The data from F 3 , &c., 

 lead to the same uncertain views as in the more definite 

 characters of the flower colours. 



The distribution of seed fuzz. The differences 

 between various strains of Egyptian cotton in this respect 

 range from complete nakedness to a woolly coat which 

 covers all but the back of the seed. The former are 

 indistinguishable from Hindi seeds, but most of them 



