112 PRACTICAL COURSE IN BOTANY 
Practical Questions 
1. Old Fort Moultrie near Charleston was built originally of palmette 
logs; was this good engineering or not? Why? (113.) 
2. Explain the advantages of structure in a culm of wheat; astalk of 
corn; areed. (113.) 
3. Would the same quality be of advantage to an oak? Why, or why 
not? 
4. Is it of any advantage to the farmer that grain straw is so light? 
5. Explain why boys can slip the bark from certain kinds of wood in 
spring to make whistles. (120.) 
6. Why cannot they do this in autumn or winter? 128.) 
7. Name some of the plants commonly used for this purpose. 
8. Is the spring, after the buds begin to swell, a good time to prune 
fruit trees and hedges? (120.) 
9. What is the best time, and why? 
10. Why are grapevines liable to bleed to death if pruned too late in 
spring? (120, 123.) 
11. Why are nurserymen, in grafting, so careful to make the cambium 
layer of t aft hit that of the stock? (120.) 
12. ta Qhototing the age of a tree or bough from the rings of annual 
growth, should we take a section from near the tip, or from the base? 
Why? (123.) 
IV. THE WORK OF STEMS 
Materiau. — Leafy shoots of grape, balsam, peach, or other active 
young stems; a cutting of willow, currant, or any kind of easily rooting 
stem. Two bottles of water and some linseed or cottonseed oil. 
EXPERIMENT 58. Do THE LEAVES HAVE ANY ACTIVE PART IN EFFECTING 
THE MOVEMENT OF SAP IN THE STEM ? — Take two healthy young shoots of 
the same kind — grape, peach, corn, tropzolum, calla lily absorb rapidly. 
Trim the leaves from one shoot and close the cut surfaces with a little vase- 
line or gardener’s wax to prevent loss of water by evaporation. Place the 
lower end of each in a glass jar or tumbler filled to the same height with 
water. Cut off under water a half inch from the bottom of each shoot, 
to get a fresh absorbing surface. This is necessary because exposure to 
air for even a second greatly hinders absorption by permitting the entrance 
of air into the severed ends of the ducts. Pour a little oil on the water in 
both jars to prevent evaporation. (Do not use kerosene; it is injurious 
to plants.) At the end of twenty-four hours, which vessel has lost the 
more water? How do you account for the difference? 
