74 



DEVELOPMENT OF FLOWERING OR PH^NOCxAMOUS 



into the soil. The root absorbs materials for the jjlant's nourish- 

 ment from the soil; these are conveyed through the stem into the 

 leaves, and there assimilated (12, 15), under the influence of the 

 light of the sun and the air, into organic matters which serve directly 

 for further growth, and form the fabric of new portions of stem, new 

 leaves, and new roots, the vegetable thus increasing its size and its 

 power at every step. 



123. Once established, therefore, the plant can provide for itself, 

 drawing the needful materials from the earth and the air, and 

 assimilating or organizing them by its own 

 peculiar power. But at the beginning, and 

 until it has sent forth its root into the soil 

 and spread out its first leaves in the light, 

 it must be nourished and grow by means of 

 organized matter supplied by the parent 

 plant. This supply in the Maple was de- 



108 



109 



no 



111 



ni" 



posited in the seed-leaves of the embryo, and was barely sufiicient 

 to develop the radicle into a tiny stem, to form a simple root at 

 the lower extremity, and above to expand in the hght the pair 

 of small, green seed-leaves ; when the plantlet is left to its own 

 resources. Very commonly a larger store of nourishment is pro- 

 vided for the plant's earliest growth. In the almond, for instance 

 (Fig. 108), the large cotyledons are so thickened by this nourishing 

 matter, deposited in their tissue, that they have not the appearance 

 of leaves. It is the same m the Plum and Cherry (Fig. Ill"), 

 and in the Apple, only on a smaller scale (Fig. 110, 111) ; and the 

 Beech (Fig. 112 - 114) and the Bean (Fig. 115-117) afford flimiliar 



FIG. 108. Embryo (kernel) of the Almond. 109. Same, with one cotyledon removed, to 

 show the plumule, a. 



FIG. 110. Section of an Apple-seed, magnified, cutting through the thickness of the 

 cotyledons. 111. Embryo of the same, extracted entire, the cotyledons a little separated. 



FIG. Ill ". Germination of the Cherry, showing the thick cotyledons little altered, and 

 the plumule developing the earliest real foliage. 



