THE TYPICAL LEAF AND ITS PARTS 27 



various substances required by the different tissues before 

 it can be appropriated by them. 



PRACTICAL QUESTIONS 



1. Why do gardeners bank up celery to bleach it ? (25.) 



2. Why are the buds that sprout on potatoes in the cellar white? (25.) 



3. Why does young cotton look so pale and sickly in long-continued 

 wet or cloudy weather ? (25.) 



4. Why do parasitic plants generally have either no leaves or very 

 small, scalelike ones ? (25.) 



5. The mistletoe is an exception to this ; can you tell why ? (184.) 



6. Could an ordinary self-supporting plant live without green 

 leaves ? (26, 27.) 



7. Are abundance and color of foliage any indication of the health 

 of a plant ? (24, 26.) 



8. Is the practice of lopping and pruning very closely, as in the 

 process called "pollarding," beneficial to a tree under ordinary con- 

 ditions ? ( 1 8, 21, 24, 26.) 



9. Why is it wise to trim a tree close when we transplant it ? 

 (20, 21.) 



10. Why should transplanting be done in winter or very early spring, 

 when the leaves are off ? ( [9, 20.) 



u. Name some plants of your neighborhood that grow well in the 

 shade. 



12. Compare in this respect Bermuda grass and Kentucky blue 

 grass ; cotton and maize ; horse nettle (Solanum carolinense) and 

 dandelion ; beech, oak, red maple, dogwood, pine, cedar, holly, mag- 

 nolia, etc. 



13. Why are evergreens more abundant in cold than in warm 

 climates ? (19, exp.) 



14. Is it wholesome to keep blooming plants in a bedroom ? Leafy 

 ones ? 



15. Why, in each case ? (23, 28.) 



THE TYPICAL LEAF AND ITS PARTS 



MATERIAL. Leaves of as many different kinds as can conveniently 

 be obtained, showing their various modes of attachment, shapes, tex- 

 ture, etc. For stipules, leaves on very young twigs should be sought 

 for, as these bodies often fall away soon after the leaves expand. The 

 rose. Japan quince {Pyrnsjaponica), willow, strawberry, pansy, pea, and 

 young leaves of apple, peach, elm, oak, beech, tulip tree {Liriodendroti), 

 India rubber tree (Ficus elastica), magnolia, etc., furnish good exam- 

 ples of stipules. 



