63.] 



GERMINATION. 



75 



of the planted seed, agriculturists are not agreed ; but 



nature seems to indicate that no covering is needed 



beyond what will secure the requisite moisture and 



shade. Thus situated, the integuments gradually ab- 



sorb water, soften, and expand. The insoluble, starchy 



matter deposited in the cotyledons, or in the albumen, 



or in both, undergoes a certain chemical change, be- 



coming sweet and soluble, capa- 



ble of affording nourishment to 



the embryo now beginning to 



dilate and develop its parts. 



First (in the winged seed of the 



Maple, scattered everywhere) the 



radicle is seen protruding from 



the micropyle, or the bursting 



coverings. A section of this 



seed would now show the folded 



embryo, impatient of confine- 



ment (225). 



191. Soon after, the radicle 

 has extended ; and, pale in color, 

 has hidden itself in the dark, 



damp earth. NOW the COtyledonS. 



unfolding and gradually 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 em- 

 bryo no longer, but a growing plant, descending by its 

 lower axis, ascending and expanding by its upper. 



192. With equal advantage we may watch the ger- 

 mination of the Beech, represented in the figures 



Germination of Wheat. o, the grain, 

 containing the cotyledon ; c , plumule ; 

 r, radicle ; , rootlets (adventitious). 



