20 



HOW PLANTS GROW FROM THE SEED. 



out of the seed, and let the root form from the lower end of it, while the plumule 

 develops from its upper end directly into a strong leafy stem. Fig. 40 is an acorn 

 cut through lengthwise. The whole kernel consists of a pair of very thick seed- 

 leaves, loaded with starch, &c., and completely enclosing the very small and short 

 stemlet, or radicle, seen at the bottom. Fig. 41 is the acorn with the seedling 

 Oak growing from it ; the seed-leaves remaining in the shell, but feeding the strong 

 root which grows downwards and the stem which shoots so vigorously upwards. 



44. Acorns and horsechestnuts may not always be found germinating ; but in 

 the Pea we ha\e a familiar case of this way of growing, which may be observed 

 at any season by planting a few peas. Fig. 42 is a pea with the seed-coat taken 

 off, after soaking. Here the seed-leaves are so thick that the pair makes a little 

 ball ; and the stout radicle or stemlet appears on the side turned to the eye. 

 Fig. 43 shows the plantlet growing. The whole seed remains in the soil ; the 

 plumule, well nourished by the great stock of food in the buried seed-leaves, alone 

 rises out of the ground as a strong shoot, bearing an imperfect scale-like leaf upon 

 each of its earlier joints, and then producing the real leaves of the plant, while the 

 radicle at the same time, without lengthening itself, sends down three or four roots 

 at once. So the whole plant is quickly established, and all the early growth is 

 made out of food provided for it the year before by the mother plant, and stored 

 up in the seed. One more illustration we may take from 



45. Indian Com. Here the 

 food provided for the early 

 growth is laid up partly in the 

 embryo, but mostly around it. 

 Fig. 44 is a grain cut through 

 flat-wise ; Fig. 45, another cut 

 through the middle across its 

 thickness ; and Fig. 46, the embryo, or germ, of another grain, taken out 

 whole, — which may readily be done in green corn, or in an old grain 

 after soaking it for some time in warm water. The separate embryo is 

 placed to match that which is seen, divided, in the seed ; r is the radicle ; 

 p, the plumule ; and c, the seed-leaf or cotyledon, which in this plant is 

 single ; while in all the foregoing there was a pair of seed-leaves. Tlie 

 greater part of the grain is the meal, or albumen, the stock of nourish- 

 ment outside of the embryo. In germinating, this meal is slowly changed 



