HOW PLANTS GROAY FROJI THE SEED. 



13 



31. The root keeps on growing under gi'ound, and sending off more and more 

 small branches or rootlets, each one adding something to the amount of absorbing 

 surface in contact with the moist soil. The little stem likewise lengthens upwards, 

 and the pair of leaves on its summit grow larger. But these soon get their full 

 growth ; and we do not yet see, perhaps, where more are to come from. But now. 

 a little bud, called the Plumule, appears on the top of the stem (Fig. 22), just be- 

 tween the stalks of the two seed-leaves ; it enlarges and unfolds into a leaf; this 

 soon is raised upon a new piece of stem, which car- 

 ries up the leaf, just as the pair of seed-leaves were 

 raised by the lengthening of the radicle or first joint 

 of stem in the seed. Then another leaf appears on 

 the summit of this joint of stem, and is raised upon 

 its own joint of stem, and so on. Fig. 23 shows the 

 same plant as Fig. 22 (leaving out the root and the 

 lower part of the stem), at a later stage ; c, c, are the 

 seed-leaves ; I is the next leaf, which came from the 

 plumule of Fig. 22, now well raised on the second 

 joint of stem ; and l' is the next, still very small and 

 just unfolding. And so the plant grows on, the whole 

 summer long, producing leaf after leaf, one l)y one, 

 and raising each on its own joint of stem, arising 

 from the summit of the next below ; — as we see in 

 Fig. 4, at the beginning of the chapter, where many joints of stem have grown 

 in this way (the first with a pair of leaves, the rest with one apiece), and still 

 there are some unfolding ones at the slender young summit. 



32. How the Seedling is nourislictl at tlie Beginning. Grotvth requires /ooJ, in plants 



as well as in animals. To grow into a plant, the embryo in a seed must be fed 

 with vegetable matter, or with something out of which vegetable matter can be 

 made. When a plant has established itself, — that is, has sent down its roots into 

 the soil, and spread out some leaves in the air, — it is then able to change mineral 

 matter (viz. earth, air, and water) which it takes in, into vegetable matter, and so 

 to live and grow independently. But at the beginning, before its organs are 

 • developed and established in their proper places, the forming plant must be sup- 

 plied by ready-made vegetable matter, furnished by the mother plant. On this 

 supply the embryo germinating from the seed feeds and grows, — just as the new- 



