310 



THE SEED. 



the former during germination, in the latter during the growth 

 of the seed. 



602. The albumen was named Perisperm by Jussieu, and 

 Endosperm by Richard (25, note) ; but neither name has in 

 systematic botany displaced the earlier one of Grew and Girt- 

 ner. But both names have recently been brought into use to 

 distinguish between two kinds of albumen, that formed within 

 the embryo-sac, which is specific-all}- termed ENDOSPERM, and that 

 formed without, which takes the name of PERISPERM. This use 

 comports with the etymology of the two words, the former refer- 

 ring to a comparatively internal and the latter to an external 

 portion of the seed or kernel. 



603. In most seeds the albumen is endosperm : in Canna it 

 is all perisperin. In Nymphsea and its allies (except Nelum- 



bium, which has none) most of it is perisperm ; 

 but a thin and condensed layer of endosperm 

 surrounds the embryo, where with the per- 

 sistent embryo-sac (or the apex of it) it 

 forms the fleshy sac in which the embryo is 

 enclosed. It is the same in the Pepper Family 

 (Fig. 679) , except that there is a larger quan- 

 tity of endosperm or inner albumen. 



604. When the nucleus of a ripe seed is hollow, as in the 

 cocoanut and nux vomica, the formation of endosperm, which 

 usually begins next the wall of the embryo-sac, has not proceeded 

 so as to fill the cavity. The embryo- sac in the cocoanut attains 

 enormous size, and the cavity is filled by the milky fluid. 



605. The texture or consistence of the albumen differs greatly. 

 It is farinaceous or mealy when, consisting mainly of starch- 

 grains, it may readily be broken down into a powder, 

 as in wheat, buckwheat, &c. ; oily, when saturated 

 with a fixed oil, as in poppy-seed ; fleshy, when 

 more compact, but readily cut with a knife, as in 

 the seed of Barberry ; mucilaginous, when soft and 

 somewhat pulp}', as in Morning Glory and Mallow, 

 but when dry it becomes fleshy or harder ; corneous, 

 when of the texture of horn, as in coffee and the 



seed of Caulophyllum ; and even bony, as in the vegetable ivory, 

 the seed of Phytelephas. It is mostly uniform ; but in the nutmeg, 



FIG. 679. Longitudinal magnified section of a seed of Black Pepper ; showing the 

 large episperm, the small endosperm in the persistent embryo-sac, and in this the 

 minute embryo. 



PIG. 680. Longitudinal section of a seed of the so-called Papaw, Asimina triloba, 

 with ruminated albumen and minute embryo. 



