16 



HOW PLANTS CROW FROM TIIK SKED. 



springing from the top oi" the first (Fig. 30). Meanwhile the root has grown 

 deeper into the soil, and sent out branches. Having now more roots below, and, 

 above, a pair of leaves besides the seed-leaves to work with, the seedling plantlet 



£8 



all the sooner makes veg- 



etable matter enough to 

 form a third pair of leaves 

 and raise them on a third 

 joint of stem (as in Fig. 

 31) ; and so it goes on, 

 step by step. This nour- 

 ishment in the embryo of the Red-Maple seed was a few weeks before in the 

 trunk of the mother tree, as a sweet sap, that is, as Maple-sugar. 



37. Variations of the Plan of Growth. In the Morning-Glory, after the pair of 

 seed-leaves, only one leaf is found upon each joint of stem (see Fig. 23 and 4). 

 In the Maple there is a pair of leaves to every joint of stem, as long as it grows. 

 In the Morning-Glory the food in the seed, for the growth to begin with, was 

 stored up outside of the embryo ; in the Maple it was stored up in it, that is, in 

 its seed-leaves. The plan is' evidently the same in both ; but there are differ- 



