MODE OF GROWTH. 



159 



place at this point, and it closes up so as to leave tbe 

 seed free in its pales or husks, from which it is easily- 

 separated. 



The stalk or stem and leaves of the wheat plant, as 

 indeed of aU the cerealia or grain plants, differ from 

 the othet grasses in contiaining a much greater amount 

 of woody fibre, often amounting, when ripe, to liiree- 

 fourths of the whole weight. It is largely composed 

 of silex, a hard, flinty substance, which gives the stem 

 its firmness and solidity, and especially its hard and 

 glossy outside coating. 



Were it not for this hard stem, 

 it could not support its weight of 

 ears or grain. It would lodge in 

 every wind, and be comparatively 

 worthless. 



The cultivated plants belonging 

 to the genus Triticum are annu- 

 als, the others are wild perennial 

 grasses. 



The root of wheat is peculiarly 

 adapted to withstand the severity 

 of the winter's cold. The main or 

 seminal root is pushed out at the 

 same time with the germ, and that 

 nourishes the plant in its early 

 growth. As many as seventy-two 

 Stalks have been known to rise 

 from a single root. 



The grain is composed to a 



great extent of starch, with a 



Kg. 131. large percentage of gluten and 



other nitrogenous bodies. 



The two prominent and most striking varieties of 



Fig. 130. 

 Hungarian Wheat. 



