168 



GERMINATION 



corn. Hi- 

 him at ft; 

 micropyle 



6; cotyledon 

 a ; plumule 



P. 



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 they reach the air (Fig. 



291. Sprout- 292. Kernel of nr ,^\ -. , , . 



Indian corn. 290), and become functional leaves. 



Caulicle at 



315. GERMINATION OF 



INDIAN CORN. Soak kernels 

 of corn. 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 ( Cau j?J e If ^ 

 caulicle at 6, the plumule at p. The emer s in g at ; piumuieatj>. 

 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 

 jj 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 elongates, par- 

 ticularly if the seed is 

 planted deep or if it 

 is kept for some time 

 confined. In Fig. 294 

 the epicotyl has elon- 

 gated from n to p. The true plumule-leaf is at 0, but 

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



