THE WALLFLOWER 119 



In the meantime the integuments have begun to 

 form ; the inner one arises first, growing out as a ring 

 of tissue at the base of the nucellus, and forming a 

 sheath around it, which soon projects beyond its free 

 end and almost encloses it (see Fig. 43, in^). The 

 outer integument next appears in like manner, just 

 below the inner one, which it soon overtakes by its 

 more rapid growth (see Fig. 43, in 2 ). Ultimately the 

 outer integument closes in over the inner, leaving only 

 the narrow micropyle as a passage leading through 

 them both to the nucellus (Fig. 43, m). In the mean- 

 time the funicle has been formed by the growth and 

 division of the cells at the base of the ovule (Fig. 

 43, .A 



Keturning to the embryo-sac, we find that it not 

 only absorbs its sister-cells, but, as it continues to grow, 

 soon attacks the epidermis of the nucellus. This also 

 is quickly digested, so that only the basal part of the 

 nucellus, lying below the embryo-sac, remains (Fig. 44, 

 4 and 5 ; Fig. 43, n), while the sides and top of the 

 sac come into direct contact with the inner integu- 

 ment (see Fig. 43). 



While these changes are going on, the nucleus 

 of the embryo-sac divides, and the two daughter- 

 nuclei travel to each end (see Fig. 44, 5). Each 

 divides again (see Fig. 44, 6), and the four nuclei thus 

 formed divide once more, so that there are now eight 

 nuclei altogether in the embryo-sac, four near each 

 end. So far the nuclei only have divided, so that all 

 the eight lie free in the protoplasm of the sac. Now, 

 however, the protoplasm at each end divides into three 



