SEEDS AND GERMINATION 



25 



Germination of Monocotyledons. — Thus far we have stud- 

 ied dicotyledonous seeds ; we may now consider the mono- 

 cotyledonous group. Soak kernels of corn. Note that 

 the micropyle and hilum are at the smaller end (Fig. 24). 

 Make a longitudinal section through the 

 narrow diameter; Fig. 25 shows it. The 



Fig. 24. — Sprout- 

 ing Indian Corn. 



Hilum at A; micro- 

 pyle at d. 



Fig. 25. — Kernel 

 of Indian Corn. 



Caulicle at b; cotyle- 

 don at a ; plumule 

 at /. 



Fig. 26.— Indian 

 Corn. 



Caulicle at c; roots emerging at 

 ;«; plumule at/. 



single cotyledon is at a, the caulicle at b, the plumule 

 at/. The cotyledon remains in the seed. The food is 

 stored both in the cotyledon and as endosperm, chiefly the 

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

 ing leaf (p, Fig. 26). 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. 26). The 

 epicotyl elongates, particularly if 

 the seed is planted 

 *\ _/ s,==av — deep or if it is 

 kept for a time 

 confined. In Fig. 

 27 the epicotyl has 

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

 other leaves grow from its sheath. In Fig. 28 the roots 

 are seen emerging from the two ends, of _the caulicle- 



Fig. 27. — Indian Corn. 



o, plumule; n to/, epicotyl. 



