PERISPEEM OR ALBUMEN OF THE SEED. 281 



embryo-sac forms little cavities or bags, which in the ripe seed remain 

 as appendages to the albumen. Seeds in which the embryo occupies 

 the entire seed, are called exalbuminous (ex, without), as Composite, 

 Cruciferae, and most Leguminosae, while others having separate albumen 

 are albuminous. The larger the quantity of albumen in a seed, the 

 smaller the embryo. In figs. 492 to 494, the relative proportion which 

 the embryo bears to the albumen or perisperm in different seeds is 

 shown; e being the embryo with its cotyledons and young root, p 

 the perisperm, t the coverings of the seed, / the funiculus or cord, 

 h the hilum, and c the chalaza. In fig. 492, the embryo is minute, 

 and occupies only a small part of the apex of the albumen ; in fig. 



493, it is larger, and has encroached on the perisperm ; while in fig. 



494, it is still more developed, much of the albumen having been 

 absorbed. 



588. The albumen varies much in its nature and consistence, and 

 furnishes important characters. It may be farinaceous or mealy, con- 

 sisting chiefly of cells filled with starch (fig. 495), as in Cereal grains, 

 where it is abundant ; fleshy or cartilaginous, consisting of thicker ceUs 

 which are still soft, as in the Coco-nut, and which sometimes contain 

 oil, as in the oily albumen of Croton (fig. 496), Bicinus, and Poppy; 

 horny, when the matter in the cells is of a hard consistence, and often 

 arranged in a concentric manner, so as nearly to fill the entire cavity, 

 as hi Date, Ivory-Palm, and Coffee. The albumen may be uniform 

 throughout, or it may present a mottled appearance, as in the Nutmeg, 

 the seeds of Anonaceae, and some Palms (fig. 497), where it is called 



ruminated. This mottled appearance depends on the endopleura or 

 inner integument forming folds on which the albumen is deposited, 

 and when the seed is ripe, these foldings of the membrane divide the 

 albumen in a sinuous or convoluted manner. 



Fig. 495. - Section of a small portion of the farinaceous perisperm or albumen of Zea Mais, 

 Indian corn, c c c, Cells. // f, Grains of starch in the cells. 



Fig. 496. Section of a small portion of the oily perisperm or albumen of Croton Tiglium. 

 c c c c, Cells, hhh, Drops of oil contained in the cells. 



Fig. 497. Vertical section of the fruit of Areca Catechu, c, Perianth. /, Pericarp, p, Rumi- 

 nated perisperm or albumen, e, Embryo. 



