IG 



SEEDLINGS. 



[section 3. 



to the large store of nutritive matter they contam, and this prevents their 

 developing into actual leaves. Correspondingly, their caulicle docs not 

 lengthen to elevate them above the surface of the soil ; the growth below 

 the cotyledons is nearly all of root. It is the little plumule or bud between 



them which makes the upward growth, and which, being well fed by the 

 cotyledons, rapidly develops the next pair of leaves and raises them upon 

 a long internode, and so on. The cotyledons all the while remain below, 

 in the husk of tiie fruit and seed, and perish when they have yielded up the 

 store of food which they contained. 



23. So, even in plants so much alike as INIaplcs, there is considerable 

 difference in the amount of food stored up in the cotyledons by which the 

 growth is to be made ; and there are corresponding differences in the ger- 



FiG. 14. One of tlie pair of keys or winged fruits of Red Maple; the seed-liear- 

 ing portion cut open to .show the seed. 15. Seed enlarged, and divided to show 

 the crumpled embryo which fills it. 16. Einhryo taken out and partly opened. 



17. Embryo which has unfolded in early stage of germination and begun to grow. 



18. Seedling with next joint of stem and leaves apparent; and 19 with these parts 

 full-grown, and bud at apex for further growth. 20. Seedling with another joint 

 of stem and pair of leaves. 



