GERMINATION. 



63 



J 90. That the seed may begin to grow, or germinate, it is first 

 planted ; or, at least, placed in contact with warm, moist soil. 

 Concerning the proper depth 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 absorb water, 

 soften, and expand. The insoluble, starchy matter deposited in 

 the cotyledons, or in the albumen, or in both, undergoes a cer- 

 tain chemical change, becoming sweet 

 and soluble, capable of affording nour- 

 ishment to the embryo now beginning: 



O O 



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 fold- 

 ed embryo, impatient of confinement 

 (225). 



191. Soon after, the radicle has ex- 

 tended ; and, pale in color, has hidden 

 itself in the dark damp earth. 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 show- 

 ing a lengthening base, its first inter- 

 node, and soon a pair of regular leaves, lobed as all Maple-leaves. 

 The embryo is now an embryo no longer, but a growing plant 

 descending by its lower axis, ascending and expanding by its 

 upper. 



1 92. With equal advantage we may watch the germination of 

 the Beech, represented in the figures above ; or of the Oak, as 

 displayed in figures 1, 2, 3, 4 ; or the Pea, or Squash, and other 

 Dicotyledons ; 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 Maple and Bean, and act as the 



Germination of Wheat. o, the grai.1, 

 containing the cotyledon; r, plumule; 

 r, radicle; s, rootlets (adventitious). 



