Ch. VII, 2] 



MORPHOLOGY OF FRUITS 



355 



the "seed-leaves" or cotyledons and the hypocotyl, as 

 shown in our figure. At this stage the embryo consists 

 mostly of meristematic tissue, though an epidermis is well 

 formed, and the fibro-vascular system begins to appear, while 



Fig. 251. — Stages in the development of a typical embryo, of Rape 

 (Brassica Napus) ; X 250. 



The embryo sac, in part, is shown on the left ; the egg cell was at its lower 

 end, and has grown into the suspensor, with the initial cell at the top. Above, 

 left, the S-celled stage of the embryo, with suspensor, shown with protoplas- 

 mic contents. Below, middle, are cross sections of the globular stages of the 

 embryo. Right, a nearly formed embryo, wath two cotyledons, the sus- 

 pensor not yet ab.sorbed. (After L. Kny.) 



the foundation for a root develops next the suspensor. 

 Meantime the endosperm is developing until it surrounds 

 the growing embryo, the suspensor becoming absorbed ; 

 and the two together finally fill the embryo sac. This 

 is the state of the embryo in some seeds (page 374) when 

 ready for germination, but in other kinds the embryo con- 



