THE STORAGE OF FOOD-RESERVES 147 



(aleurone grains) or crystals, which may be either dis- 

 tributed generally throughout the storage cells, or rele- 

 gated to a special layer, as in wheat. The seeds of 

 leguminous plants — e.g., peas, beans, lentils, pea-nuts — 

 are very rich in proteins, which occur in the form of 

 aleurone grains scattered throughout all the cells. 



Fio. 53. — Fouk-Seedbd Dbtjpb of Holly. (Maonifibd.) 



1, entire fruit ; 2, transverse section ; 3, longitudinal section, u, outer 

 skin ; b, succulent part ; c, stone ; d, seed, with minute embryo em- 

 bedded in endosperm. 



(c) Fats and Oils. — These are either derived from 

 carbohydrates, or they may be produced by the dis- 

 integration of proteins. Well-known oily seeds are nuts 

 (hazel, walnut, coconut), castor-oil seeds, linseed, etc. 



Fio. 54. — Longitudinal Sbction 

 or Albuminous Seed or Poppy. 

 (Magnified.) 



a, seed-coat ; b, endosperm ; c, em- 

 bryo. 



Fio. 55. — ^Longitudinal Section 

 of Fruit op Garden Nastur- 

 tium, SHOWING EXALBUMINOUS 



Seed. (Magnified.) 



a, fruit-wall (pericarp) ; b, seed- 

 coat ; c, young root ; d, young 

 shoot ; e, scod-leaves. 



Starchy seeds constitute the most important source of 

 food to man. In most civilized nations one or other of 

 the cereal grains forms his staple diet — e.g., wheat, from 

 which white bread is made ; rye, made into black bread on 



