SEED. 65 



544. The mouth of the foramen (461) is often distinctly 

 visible, and is named the micropyle ; Ex. Pea. 



545. The raphe 279 285 occupies one side of the seed in all 

 cases in which it pre-existed in the primine ; but it frequently 

 becomes much ramified. 



546. The raphe is in no way connected with impregnation ; 

 its functions being apparently confined to maintaining a 

 vascular connection between the placenta and the base of the 

 nucleus, for the purpose of nourishing the latter. 



547. Spiral vessels are found in the raphe and its ramifica- 

 tions. 



548. Where vessels of the raphe expand into the mesosperm 

 (543), the chalaza (459) appears as a discoloured thickening 

 of the integuments 285 . 



549. The micropyle always indicates the point in the cir- 

 cumference of a seed towards which the radicle (561) points. 



550. And the chalaza is as constant an indication, when it 

 is present, of the situation of the cotyledons (559) ; it being 

 always at that part of the circumference organically opposed 

 to the radicle. 



551. Between the integuments and the embryo of some 



plants lies a substance called the albumen or perisperm"" 1 * 293 

 299, 



552. It consists of a peculiar matter deposited during the 

 growth of the ovule among the celullar tissue of the nucleus 

 (450). 



553. When the cellular tissue of the nucleus combines with 

 the deposited matter so completely as to form together but 

 one substance, the albumen is called solid ; Ex. Wheat, 

 Euphorbia. When a portion of the tissue remains uncon- 

 verted, the albumen is ruminated ; Ex. Anona, Nutmeg. 



554. Albumen is usually wholesome, and may be fre- 

 quently eaten with impunity in the most dangerous tribes ; 

 Ex. Omphalococca, a genus of Euphorbiacese. 



555. The organised body that lies within the seed, and for 

 the purpose of protecting and nourishing which the seed was 

 created, is the Embryo"* 8 . 



556. The embryo was originally included within the sac of 

 the amnios (465). 



557. The latter is usually absorbed or obliterated during 



