THE EMBRYO AND THE SEED 



275 



entiates into two regions ■ a free apical part which develops into the 

 massive Embryo, and an attached basal part which remains filamen- 

 tous. This is called the Siispensor, since it holds the embryo in a 

 definite position during its early development, surrounded, and 

 nourished by the semi-fluid contents of the enlarging sac. 



The Embryo. 



Among Dicotyledons the embryo of Capsella, the Shepherd's 

 Purse, in which the development was first followed out in detail, 



KiG. 217. 

 Embryos of Capsella hi various stages of development, (i.-v. after Famintzin ; 

 vi.-viii. after Hanstein.) The hypophysis and its products are shaded. .All these 

 embryos have the apex upwards, and the root downwards. But it is to be remem- 

 bered that the root always points to the micropyle of the ovule, as seen in Fig. -18. 



serves as a very general type. The filamentous pro-embryo (Fig. 217, i.) 

 has the cell at its basal, or micropylar end greatly enlarged. The cell 

 at the apical end is relatively small at first, but it gives rise to the 

 greater part of the embryo, a smaller part originating from the next 

 lower cell. The apical cell enlarges into a spherical form, and divides 

 into octants, by walls at right angles to one another and to the outer 



