10 



SEEDS AND SEEDLINGS 



Sprouting Process. — When the seed sprouts the root and 

 stem of the embryo plant elongate, the one growing downward 

 and the other upward ; in some seeds the cotyledons remain un- 

 derground as in the case of the corn and the pea (Figs. 4 and 6), 

 while in other young plants the cotyledons are carried above 

 ground as in the case of the squash and the bean. (Figs. 7 and 

 8.) It is very important that seeds should not be planted too 



Fig. 5. Fig. 6. 



Fig. 5. — Bean seedling showing cotyledons and first leaves. 

 Fig. 6. — Pea seedling. The cotyledons remain below the ground. 



deep, but this is especially important in the case of those seeds 

 which lift the cotyledons above the ground. The raising of the 

 cotyledons above the ground is due to the elongation of the stem, 

 and deep planting requires unnecessary growth and tends to the 

 production of a weak plant. 



The cotyledons are the first leaves of the young plant and 

 when raised above ground they perform the duties of foliage 

 (Figs. 5, 7 and 8), which wall be described later. (Page 11). 

 We have already learned that they may also serve as storage 



