130 THE OAK. 



morphological meaning in the light of modern biology, 

 but the limits and purpose of this little book will not 

 admit of that, and I must content myself with this brief 

 resume. 



During this process of fertilization the cupule has 

 grown up like a scaly wall round the ovary (Fig. 34), and 

 the tip of the latter is seen peeping out from its orifice. 



We are now in a position to understand generally 

 the changes that convert the female flower into the 

 cupped acorn The fertilized oospore becomes the em- 

 bryo (Fig. 35, x) ; it grows at the expense of the con- 

 tents of the embryo-sac, and develops a radicle, a plu- 

 mule, and two relatively large cotyledons, which soon 

 become so big that they occupy the whole space in the 

 sac (Fig. 36). Moreover, the embryo-sac increases to 

 make more room for this growing embryo. And now 

 comes in a curious point. We saw that the ovary con- 

 sisted of three chambers, each containing two ovules ; 

 each of these six ovules also had its embryo-sac, contain- 

 ing an egg-cell, etc., and each of the total of six egg- 

 cells may be fertilized by the contents of so many pollen- 

 tubes coming from pollen grains on the stigmas. But 

 the rule is that five of the ovules with their contents 

 perish at an early period, because one strong one takes 

 the lead in development, and starves the rest by taking 

 all the available nourishment to itself. Consequently 

 the advancing ovary is soon filled by one ovule the 

 other five and two of the chambers being pressed to one 

 side by it. 



