168 



GEEMINATION 



291. Sprout- 

 ing Indian 

 corn. Hi- 

 lum at h ; 

 micropyle 

 at d. 



of corn. 



192. Kernel of 

 Indian corn. 

 Oauliele at 

 6; cotyledon 

 a ; plumule 

 V- 



287). The bean "comes up" with a loop, which indicates 

 that the hypocotyl greatly elongates. On examining a 

 germinating seed, however, it will be found 

 that the cotyledons are contained inside a fleshy 

 body or sac (a, Fig. 288). This sac is the en- 

 dosperm. To its inner surface the 

 thin, veiny cotyledons are very closely 

 appressed, absorbing its substance 

 (Fig. 289). The cotyledons increase 

 in size as the}' reach the air (Fig. 

 290), and become functional leaves. 



315. GERMINATION OF 

 INDIAN CORN. Soak kernels 

 Note that the micropyle and hilum 

 are at the smaller end (Fig. 291). 

 Make a longitudinal section through 

 the narrow diameter ; Fig. 292 shows 

 it. The single cotyledon is at a, the / cauiieie iit d cT root's 

 caulicle at 6, the plumule at p. The inat s piumuieat*. 

 cotyledon remains in the seed. The food is stored 

 both in the cotyledon and as endosperm, chiefly the lat- 

 ter. The emerging shoot is the plumule, with a sheath- 

 ing leaf (p, Fig. 293). The root is emitted from 

 the tip of the caulicle, c. The caulicle is held in a 

 sheath (formed mostly from the seed -coats), and 

 some of the roots escape through the 

 upper end of this sheath {m, Fig. 

 293). The epicotyl elougates, par- 

 ticularly if the seed is 

 ,/ ,===a *- planted deep or if it 

 is kept for some time 



/ / 294. Indian corn. o. plumule; 



J I n top, epicotyl. confined. Ill Fig. 291 



the epicotyl has elon- 

 gated from n to p. The true plumule-leaf is at o, but 

 other leaves grow from its sheath. In Fig. 295 the roots 



