STRUCTURE OF THE BOLL 61 



the " style " of the flower, which protrudes through the hole 

 in the centre of the cylindrical brush of stamens, and is 

 (I 'stiiied to receive the pollen-grains which effect fertilization. 

 The bodies of these flasks similarly adhere, and form 

 according to the number of flasks an ovary, consisting of 

 two, three, four, or five loculi, and ultimately a boll, which 

 will op3n into two, three, four, or five divisions, or " locks." 



On the inner wall of the body of each flask (Fig. 11, A, c') 

 there next appears a double row of small protuberances, from 

 which are formed the ovules, and consequently after fer- 

 tilization the cotton-seeds. Each of these protuberances 

 as it enlarges forms round its base two annular swellings, 

 first a lower one, and then another above it; these are the 

 beginnings of the seed-coats. The embryonic seed-coats 

 grow up over the protuberance on which they are formed, and 

 completely enclose it in a double jacket (Fig. 11, A, d, e,f, g), 

 excepting for a minute hole at the top, through which the 

 fertilizing pollen-tube will ultimately enter. Until fertiliza- 

 tion has been accomplished, these seed-coats are of uniform 

 structure internally, excepting that the outermost and inner- 

 most cell layer of each can be distinguished as an epidermis. 

 The outer epidermis of the outer coat gives rise to the cotton- 

 fibre itself (Fig. 11, A, k- C, a, b, c; Fig. 13). 



THE FLOWER (PI. III.). The processes so far described 

 have taken place during twenty-three days, and when 

 the flower opens on the morning of the twenty-fourth 

 day it consists of three leafy bracts, about three inches 

 long, cut into long narrow teeth (in many cottons), en- 

 closing an inconspicuous green calyx-ring, frjom within 

 which rises the bell or trumpet shaped corolla, with its 

 brush of stamens, and the more or less protruding style. 

 By about 9 a.m. on the day of flowering the corolla is 

 fully expanded, and the sacs of pollen are gaping open, 



