STRUCTURE OF THE BOLL 83 



lint first originates by the protrusion of individual 

 epidermal cells. There does not appear to be any further 

 growth of epidermal cells into lint hairs after this first 

 day, in spite of accepted statements to the contrary. 

 The density of the lint on a given area of seed-coat should 

 thus, other things being equal, depend on the circum- 

 stances of the environment on the day when the flower 

 opens. We shall see in the next chapter that there is 

 some indication of this being the case. 



Fuzz. The hairs of the fuzz are distinguishable from 

 those of the lint by their much greater diameter, even in 

 the earliest stages of their development. They are as a 

 rule about twice the diameter of a lint hair, or more. 

 They arise in much the same way, at the same time, and 

 from the same layer of cells. We discussed some of the 

 interesting features of this velvety covering in an early 

 chapter, and, except by showing the markedly greater 

 size of the hairs, the microscope has thrown no further 

 light on its significance, nor on its evolutionary relations 

 to the lint. 



We have now traced the main outlines of the details 

 involved in the development of an average cotton boll. 

 A tabular statement of the dates and corresponding stages 

 in its life is appended, by the help of which, and of the 

 diagrams (Fig. 13), it should not be too troublesome for 

 the non-botanist to recapitulate the story. 



We now pass to a more living account of the develop- 

 ment, in which the play and elasticity of the structures 

 we have descrited are demonstrated under the ebb and 

 flow of environmental conditions. 



