IWZ 



GERMINATION. 



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

 embryo impatient of confinement. 



irf Xy •; 



181 



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

 476 — 480, Progressive stages. 



612. The process concludbd. Soon the radicle has extended, and, 

 pale in color, has hidden itself ini the bosom of 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 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 beoomes 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, jis 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, 



^ , u . wv .. ..1. 1 buok-eye, oak (6 — 9); they remain as first 

 Germination of Wheat; o, the grain , , .o ^, „ ,o ,■,o^ .,, , 



containing the cotyledon ; c, plumulej r, Plaoed with the ooUum (§ 118), neither ascend- 



radicle; «, rootlets (adventitious).' ingnor 



