PLANTS FROM THE SEKD. 71 



plantlet in a rudimentary state. Flowerless or Cryptogamous plants 

 spring from spores or single cells, which when they germinate multi- 

 ply to produce a tissue or an aggregation of cells, that at length 

 grows and forms a plantlet. But a seed contains a plantlet ready 

 formed, or a germ, which is called an Ejibryo. And the history of 

 a Flowering or Pluenogamous plant naturally begins with 



119. The Development of llie Embryo from the Seed. The embryo 



varies exceedingly in size, shape, and appearance in different plants ; 

 but it is constructed upon the same general plan in all ; and the 

 development of almost any plantlet from the seed will serve to illus- 

 trate the principal laws and processes of vegetable growth. To 

 commence with the study of the seedhng is the readiest way to un- 

 derstand the whole vegetable structure and life. 



120. The seeds of the Red or the Sugar Maple furnish good 

 illustrations, and they are readily met with in germination, i. e. just 

 developing the embryo into a plant. Also they are large enough to 

 allow the embryo to be extracted from the seed-coats, and inspected 

 by the ntiked eye, or by the aid of a common hand-glass. (Fig. 

 103-105.) Here 



the whole contents ^-—^^ /C^^^ 



of the seed consist 

 of an embryo, neatly 

 coiled up Avithin the 

 seed-coats. If un- ^^^ ,^ 105 



folded, or, which is 



better, if examined when just unfolding itself in germination, it is 

 seen to consist of a tiny stem or axis (Fig. 104, 105, a), bear- 

 ing a pair of small leaves on its summit. The axis is called the 

 Radicle, because it was supposed to be the root ; though it is really 

 the rudiment of the stem rather than of the root, and therefore were 

 better named the Caidicle ; but the former name is now too well 

 established to be superseded. The two little seed-leaves {h, h) are 

 technically called Cotyledons : and a little bud which will pres- 

 ently appear between them (Fig. 106, c), or may be discerned there 

 in many embryos before germination (as in the Almond, Fig. 

 108, a) is named the Plumule. The embryo, accordingly, is a 

 short axis or stem bearing upon one end some rudimentary leaves ; 



FIG. 103. Embr3'0 of Sugar-Maple as coiled up in the seed. 104, 105. The same, just be- 

 ginning to unfold and develop in germination : a, the radicle, or primary stem : i, 6, the 

 cotyledons or seed-leaves. 



