ANTHOPETTA. 257 



a storage of starch or oily matter in some part of the em- 

 bryo. While the embryo is growing inside of the ovule, 

 the outer ovule-coat generally becomes thicker and harder, 

 all the ovule-tissues become drier, and at last the hard, 

 dry ovule, now called a seed, separates at its base and falls 

 to the ground. 



483. The seed in germinating absorbs moisture, swells 

 up, and generally bursts its coat. The embryo resumes its 

 growth, sending out its root into the soil, and its stem and 

 leaves upward into the air. Where there is endosperm, 

 the embryo grows by absorbing food from it; where there 

 is no endosperm, the large embryo is strong enough to grow 

 for a time by using the store of food contained within 

 itself. In some cases (e.g., beans, squash, melon, etc.) all 

 the leaves withdraw from the seed-coat and appear above 

 ground, while in others the first one or two leaves (cotyle- 

 dons) remain in the seed in the ground, only the succeed- 

 ing leaves coming up into the light and air, as in peas, 

 wheat, etc. 



484. We have seen that fertilization of the germ-cell 

 not only caused the latter to develop into a plantlet, but 

 excited the tissues of the ovule to a growth which they 

 would not have made otherwise. This excitation of growth 

 extends much further than the ovule ; it commonly causes 

 the ovary to undergo considerable changes, and in some 

 cases even parts of the perianth or the stem which bears 

 the organs of the flower. These changes give rise to the 

 fruit of Angiosperms. 



485. The changes which most frequently take place in 

 the growth of the fruit are such as (1) an increase in the 

 number of ovule-chambers by the formation of false par- 

 titions, or (2) a decrease in their number by the oblitera- 



