Seeds and their Germination 



13 



a lens small channels can be seen through which the food 

 passes to the growing parts. The radicle was protected in the 



Fig. 17, — Cala- 

 bash. The peg 

 has done its 

 work for the 

 little calabash 

 plant. 



Fig. 18. — Germinat- 

 ing embryo of Zea 

 mays. c, cotyle- 

 don ; r, radicle ; 

 sr, first side shoots 

 growing from stem. 



Fig. 19. — Germinating bean seeds ; 

 a and b with one cotyledon 

 removed. 



seed by a little pocket, as was the leaf. The cap does not 

 grow as much as the leaf- cap does, and the radicle soon pushes 

 through it. 



In Zea mays (mealie) the first side roots come from the 

 stem just above the scutellum. They are a part of the embryo. 

 In the pumpkin they come from the radicle which forms the 

 tap root ; they are not formed until after the root begins to 

 grow. 



Compare the germination of a common bean and that of 

 a broad bean. Both come up with a loop. Does the same 

 part of the stem form the loop? How do the cotyledons 

 behave in the kidney bean and in the broad bean? The 

 cotyledons do not grow as in the calabash or pumpkin. Notice 

 how they wither as the food they contain is given up to the 

 growing parts. When the loop pulled up the cotyledons in 

 the kidney bean, the tender leaves of the plumule folded 

 between them were also safely brought up. The plumule 

 grows out into two green leaves. Notice the little cushions 



