122 



GERMINATION. 



bursting integument. A section of this seed would now show the folded 

 embryo impatient of confinement. 



Germination of the Maple. 475, Samara ; section showing the folded cotyledons at c. 

 476 ISO, Progressive stages. 



612. THE PROCESS CONCLUDED. Soon the radicle has extended, and, 

 pale in color, has hidden itself in the bosom of the dark, damp earth. 

 481 482 Now the cotyledons, unfolding and grad- 



ually freed from the seed coats, display 

 themselves at length as a pair of green 

 leaves. Lastly the plumule appears in 

 open air, a green bud, already showing 

 a lengthening base, its first internode, 

 and soon a pair of regular leaves, lobed 

 as all maple leaves. The embryo is 

 now an embryo no longer, but a grow- 

 ing plant descending by its lower axis, 

 ascending and expanding by its upper. 

 613. WHAT BECOMES OF THE COTYLEDONS. 

 The germination of the tulip-tree, oak, pea, 

 squash, and other Dicotyledons maybe watched 

 with equal advantage, and the chief difference 

 observed among them will be in the disposal 

 of the cotyledons. In general, these arise with 

 the ascending axis, as in the maple and bean, 

 and act as the first pair of leaves ; but some- 

 times, when they are very thick, as in the pea. 



Germination of Wheat; o, the grain ^^ * V^A""^ * "T 

 containing the cotyledon ; c, plumule; r, P laced wlth the collura ( 118 )' neither ascend - 

 radicle; , rootlets (adventitious). ing nor descending. 



