PRACTICAL WORK. NO. II. 203 



II. Seedling. 



iii. Make a sketch of a germinating bean, showing 

 the radicle emerging near the micropyle. Remove the 

 seed-coat or testa and split open the bean longitudinally : 

 sketch your preparation, showing on your sketch 



a. the radicle ; 



6. the plumule ; . 



c. the cotyledons or seed-leaves. 



iv. Sketch a bean seedling, showing the ruptured 

 seed-coat, the root and its branches, the stem and the 

 leaves. 



v. Show on your sketch of a germinating Cucurbita 

 seed 



a. seed-coat or testa ; 



b. radicle; 



c. peg or heel which holds down one part of the seed- 

 coat to permit the cotyledons to leave it ; 



d. cotyledons and the hypocotyledonary axis (hypo- 

 cotyl); 



e. plumule. 



vi. Sketch an older seedling, showing its stem, coty- 

 ledons, leaves differing in shape from the cotyledons, and 

 the growing apex. 



III. Tuber. 



i. Examine a tuber of the Jerusalem Artichoke 

 (Helianthus tuber osus), which is a swollen stem bearing 

 several buds. Make a sketch, showing that these buds 

 occur singly in the axils of scale leaves. 



