154 PRACTICAL COURSE IN BOTANY 
2. How would you distinguish between a chinquapin, a chestnut, a 
chestnut oak, and a horse-chestnut tree by their leaves alone? By their 
bark and branches? Between a hickory, ash, common elder, box elder, 
ailanthus, sumach? Between beech, birch, elm, hackberry, alder? 
(Any other sets of leaves may be substituted for those named, the object 
being merely to form the habit of distinguishing readily the differences 
and resemblances among those that bear some general likeness to one 
another.) 
3. From the study of these or similar specimens, would you conclude 
that resemblances in leaves are confined to those of closely related kinds? 
4. Name some causes independent of botanical relationship that might 
influence them. (169, 170; Exps. 48, 57.) 
5. Do you find, as a general thing, more leaves with stipules or without? 
6. Is their absence from a mature leaf always a sign that it is really 
exstipulate? (166.) 
7. Can you trace any line of development through intervening forms 
from a merely sessile leaf, like that of the pimpernel or specularia, to a 
peltate one? (Figs. 184-187, and observation of living specimens.) 
8. Does the leaf determine the position of the node, or the node the 
position of the leaf? 
9. Strip the leaves from a twig of one order of arrangement and replace 
them with foliage from a twig of a different order; for instance, place 
basswood upon white oak, birch upon lilac, elm upon pear, honeysuckle 
upon barberry, etc. Is the same amount of surface exposed as in the 
natural order ? 
10. What disadvantage would it be to a plant if the leaves were arranged 
so that they stood directly over one another? (169.) 
11. Why are the internodes of vigorous young shoots, or scions, gen- 
erally so long? (150.) 
12. If the upward growth of a stem or branch is stopped by pruning, 
what effect is produced upon the parts below, and why? (152, 153.) 
13. Give some of the reasons why corn grows so small and stunted when 
sown broadcast for forage? (60, 63, 169.) 
14. What is the use of “chopping” (7.e. thinning out) cotton? 
Il. THE VEINING AND LOBING OF LEAVES 
Mareriau. — Leaves of any monocotyl and dicotyl will show the dif- 
ference between parallel and net-veining. To illustrate the palmate and 
pinnate kinds, the leaves of grasses and arums may be used for monocotyls, 
and for dicotyls, those of ivy, maple, grape, elm, peach, cherry, etc.; for 
division, examine lobed and compound leaves of as many kinds as are 
attainable. A specimen showing each kind of veining should be placed in 
