«4 



SEED. 



[chap. 



observe at one end of the hilum a very minute aperture 

 through the skin of the seed. You may find it by squeezing 

 the soaked seed, when moisture issues from it. This is the 

 viicropyle; it answers to the micro pyle of the ovule (see 

 page 26). Generally, in ripe seeds, it is obliterated, or too 

 minute to be observed. 



As soon as the testa is removed, you find that its entire 

 contents easily separate into halves, each half being plane 

 on the inner face, and rounded on the outer. Observe, 

 also, that these halves or lobes are hinged together at one 

 side. Separate the lobes carefully, and you may observe 

 upon the margin of the inner face of one of the lobes, close 

 by the hinge, a rudimentary bud and root. You find, then, 

 enclosed by the testa, (i) one pair of large seed-leaves ; 



Fig. 10. Embryo of Pea with the 

 cotyledons laid open, showing 

 the curved plumule and radicle. 



Fig. II. Seed of .same before removal of 

 the testa, showing the hilum and ridge 

 above indicating the position of the 

 radicle inside. 



(2) a bud with minute, rudimentary foliage-leaves; and 



(3) the rudiment of a root. Nothing more. These parts 

 are indicated in the cut, which shows the seed-leaves with 

 their inner faces exposed. The seed-leaves are called coty- 

 ledons. To the right is the bud of the stem, slightly curved 

 inwards, called the pliimide; and, pointing downwards, the 

 rudiment of the root, called the radicle: the extremity of the 



