CHAP. 11 SEEDLINGS 15 



3. The short caulicle has not lengthened at all, but has given 



rise to one or more primary roots from its tip. 



4. Very old seedlings will show the tip of the cotyledon 



withering away and losing the now emptied seed- 

 coats, while the plumule emerges from a longitudinal 

 slit at the base. 



5. Make a series of sketches to show these points. 



IX. Take some Pine Seedlings (of different ages if possi- 

 ble) and notice that : 



1. The lengthening caulicle bends to form a loop and pulls 



the cotyledons with the seed-coat and endosperm 

 out of the ground. (This does not always happen, 

 however, in the species with large seeds or " nuts.") 



2. The spreading cotyledons cast off the seed-coats and 



expand to form a circle or whorl of needle-shaped 

 leaves. 



3. The plumule appears only after some time has gone by. 



4. Make a series of sketches to show these points. 



X. In order that an ordinary seed may germinate, it is 

 placed usually in a light soil whose particles have been 

 loosened, well watered, and kept warm. We may infer 

 from this that access of air, water, and a sufficiently high 

 temperature are necessary. 



1 . Place dry Peas in dry, loose sawdust, add no water, keep 



in a warm place, and watch several days, after which 

 uncover the Peas and examine to see whether any 

 changes have taken place. 



2. Place dry Peas in dry, loose sawdust, occasionally sprin- 



kle well with water, keep in a warm place, watch, and 

 examine as in (i). 



