170 THE VEGETABLE WORLD. 
matter, from which the embryo draws the substances necessary for 
its first growth. This body is the albumen. When this is wanting, 
the cotyledons perform the functions of the nurse, nourishing the 
: young plant, and it is to this end that they undergo 
the modification of which we have just spoken. Thus, 
in the seed of the Bean, which has no albumen, the 
cotyledons are much developed and full of a nutritive 
substance, of which the embryo takes a considerable 
portion. In the seed of Ricinus, which encloses a 
considerable portion of albumen, the cotyledons pre- 
serve the characteristics peculiar to the organs they 
represent ; they are thin and foliaceous. The albumen 
varies very much in its bulk, nature, and position, in 
" Fig. 263.—Cary. Tegard to the embryo, consisting of amylaceous, lig- 
TT  heoak, , and saccharine matters; with oils, 
resins, salts, and other heterogeneous substances. It is very con- 
siderable in Wheat (Fig. 263) and in Ivy (Fig. 264) ; it is reduced 
to a thin layer in Ketmia Adansey, the Hibiscus of modern 
botanists. In wheat, the embryo is placed laterally at the base of 
a ee eee 
the albumen, completely enclosing it in the Wigella arvensis (Corn 
Cockle), Fig. 265; it is, on the contrary, surrounded on all sides 
in the seed of the Wood-Sorrel (Oxalis), Fig. 266. 
Albumen is almost exclusively formed of cellular tissue. We 
observe in it neither fibres nor air vessels. These cells have some- 
times thin walls, as in the Ricinus, Wheat, and other cereals; 
sometimes their walls are very strongly thickened, as may be seen 
in the horny and firm tissues of the Date-stone (Fig. 267), which 
is only the albumen of the seed. In the albumen of Wheat and 
other cereals, fecula predominates in the cells. The form of the 
starchy grains, varying with the species, is not unimportant. — 
