16 



SUGAR BEET SEED. 



cells form, they attach themselves to the narrow part of 

 the sac, the' larger part formingf the cotyledon. 



Enlarged Microscopical Section of the Entire 

 Seed. 



The engraving (Fig. 13) is a section of beet seed 

 made by Drs. Westler and Stoklasa. It shows what 

 the conditions are much more satisfactorily than 

 the drawing we have made aijd described in this 

 writing. C are the two cotyledons; r, radicle; p, peri- 

 sperm ;e, endosperm (albumen found inside the embryo- 

 sac); t, testa. The endosperm in most cases con- 

 sists of only one layer, while the testa has two: ist, the 

 yellow, which consists of a single layer of cellulose; 

 2d, the brown, which is possibly made up of two flat 

 layers. The curved germ r, radicle, and c, its two 



Fig. 18. Section M. N. 



Fig. 19. Starch cell. 



cotyledons, retains the perisperm tissue; the cells are 

 very fatty, and the starch granules appear round or 

 elliptical. The lower portion of radicle (r) is covered 

 with a layer (/) of endosperm, which may be detached, 

 and consists of one layer of elongated cells. The cells 

 of which the radicle and cotyledons consist, hold fatty 

 but not starchy granules. 



It frequently happens, just as it does in animal 

 physiology, that the oviim is not fertilized; it then 

 withers and disappears, the explanation of which con- 



