36 THE SEED. [CHAP. 



Observe, first, the black stripe on the edge of the seed. 

 This indicates the part by which the seed was attached to 



FIG. 26. Seed of Bean. The black FIG. 27. Seed of same, the testa 



line at the bottom of the seed is the being removed. On the left is 



hilum. The letter m indicates the the radicle, pointing downwards ; 



position of the micropyle. its extremity corresponding to 



the micropyle. 



the fruit-carpel (pericarp} in which it was enclosed ; it is 

 the scar left on its separation from it. It is called the 

 hilum. On careful examination you may 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 micro- 

 pyle j it answers to the micropyle of the ovule. It is 

 usually obliterated or too minute to be observed in ripe 

 seeds. 



Proceed, now, to remove the skin of the seed (testa], 

 You find it contains two large thickened lobes or leaves, 

 each^ flattened on the inner side, rounded on the outer, 

 and you also notice that these lobes are hinged 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, (2) a bud with minute, rudimentary foliage- 

 leaves, and (3) the rudiment of a root. Nothing more. 

 These parts are indicated in the cut (Fig. 28), which shows 

 one seed-leaf seen on its inner face. The seed-leaves are 

 called cotyledons. , To the left is the bud of the stem, 



