362 



EMBRYO OF ANGIOSPERMS 



different origin from the gametophyte of the gymnosperms, which 

 is unfortunately also often called the endosperm. 



The germination of the gametospore and the formation of the 

 embryo vary so greatly that only a very general statement can 

 be made. Following fertilization, the gametospore becomes sur- 



Fig. 274. Sectional view of megasporophylls of Lcpidium shortly after 

 fertilization (see Fig. 269) : en, early development of endosperm cells 

 about wall of embryo sac ; p, young sporophyte developing from gameto- 

 spore; mi, micropyle; s, stigma; f, funiculus. 



rounded by a cell wall and attached to the wall of the embryo 

 sac (Fig. 275, A). The first division of the gametospore is trans- 

 verse, resulting in the formation of an outer cell, i. e., facing the 

 micropyle, and an inner daughter cell. The outer cell divides 

 several times, usually in the same plane, forming a row of cells 

 (known as the suspensor) which push the inner daughter cell 

 (called the embryo cell) into the cavity of the embryo sac. The 

 suspensor and embryo cell constitute the pro-embryo (Fig. 

 275. B). The synergids, which are partly consumed during the 

 entrance of the tube cell and the process of fertilization, usually 

 become entirely disorganized and absorbed during these early 

 stages of germination. The embryo is formed by the repeated 



