LESSON 3.] GROWTH OF THE PLANT FEOM THE SEED. 



11 



the same thing on a smaller scale. The embryo, which here also 

 makes up the whole bulk of the kernel of the 

 seed, differs from that of the Pumpkin only 

 in having the seed-leaves more thickened, bj 

 the much larger quantity of nourishment stored 

 up in their tissue, — so large and so pure in- 

 deed, that the almond becomes an article of 

 food. Fed by this abundant supply, the second, 

 and even the third joints of the stem, with 

 their leaves, shoot forth as soon as the stemlet comes to the surface ol 

 the soil. The Beech-nut (Fig. 13), with 

 its sweet and eatable kernel, consisting 

 mainly of a pair of seed-leaves folded 

 together, and gorged with nourishing 

 matter, offers another instance of the 

 same sort : this ample store to feed 

 upon enables the germinating plantlet 

 to grow with remarkable vigor, and to 

 develop a seco'hd joint of stem, with its 

 pair of leaves (Fig. 14), before the first 

 pair has expanded or the root has ob- 

 tained much foothold in the soil. 



28. A Bean affords a similar and 

 more familiar illustration. Here the co- 

 tyledons in the seed (Fig. 16) are so 

 thick, that, although they are raised out 

 of ground in the ordinary way in ger- 

 mination (JFig. 17), and turn greenish, 

 yet they never succeed in becoming leaf- 

 like, — never display their real nature of 

 leaves, as they do so plainly in the Ma- 

 ple (Fig. 5), the Pumpkin (Fig. 10), the 

 Morning-Glory (Fig. 8, 26-28), &c. 

 Turned to great account as magazines 

 of food for the germinating plantlet, they 

 fulfil this special office admirably, but 



FIG. 11. An Apple-seed cut through lengthwise, showing the embryo with its thickened 

 cotyledons. IS. The embryo of the Apple, taken out whole, its cotyledons partly separated. 



FIG. 13. A Beecli-nut, cut across. 14. Beginning germination of the Beech, showing the 

 plumule growing before the cotyledons have opened or the root has scarcely formed. 15. The 

 fame, a little later, with the second joint lengthened. 



