THE LEAF 159 



creeper, and one of rose, black locust, or vetch. Notice that 

 each of these last is made up of entirely separate divisions or 

 leaflets, thus forming a compound leaf. Notice also that the 

 two kinds of compound leaves correspond to the two kinds of 

 veining and lobing, so that we have palmately and pinnately 

 compound ones. In pinnate leaves the continuation of the 

 common petiole along which the leaflets are ranged is called 



the rhachis. 



Practical Questions 



1. In selecting leaves for decorations that are to remain several hours 

 without water, which of the following would you prefer, and why: 

 smila^ or Madeira vine (Boussingaultia) ; ivy or Virginia creeper ; 

 magnolia or maple; maidenhair or shield fern (Aspidium)? (173.) 



2. Would you select very young leaves, or more mature ones, and why ? 



3. Can you name any parallel- veined leaves that have their margins 

 lobed, or indented in any way ? 



4. Which are the more common, parallel- veined or net- veined leaves ? 



5. Why do the leaves of corn and other grains not shrivel lengthwise in 

 withering, but roll inward from side to side? (173.) 



6. Can you name any palmately veined leaves in which the secondary 

 veins are pinnate ? Any pinnately veined ones in which the secondary 

 veins are palmate ? 



7. Lay one of each kind before you ; try to draw a pinnate leaf with 

 palmate divisions. Do you see any reason now why these so seldom occur 

 in nature ? 



8. Name some advantages to a plant in having its leaves cut-lobed or 

 compound. (169.) 



9. Mention some circumstances under which it might be advantageous 

 for a plant to have large, entire leaves. (169; Plate 9.) 



10. How would the floating qualities of the leaves of the pond lily be 

 affected if their blades were cut-lobed or compound ? 



11. Do the leaves of the red cedar and arbor vitae contribute to their 

 value as shade trees ? 



12. Name some of the favorite shade trees of your neighborhood ; do 

 they, as a general thing, have their leaves entire, or lobed and compound ? 



13. Which of the following are the best shade trees, and why : pine, 

 white oak, mimosa (Albizzia), sycamore, locust, horse-chestnut, fir, maple, 

 linden, China tree, cedar, ash ? 



14. Which would shade your porch best, and why: cypress vine, 

 grape, gourd, morning-glory, wistaria, clematis, smilax, kidney bean, 

 Madeira vine, rose, yellow jasmine, passion flower? 



