112 PRACTICAL COURSE IN BOTANY 



Practical Questions 



1. Old Fort Moultrie near Charleston was built originally of palmetto 

 logs; was this good engineering or not ? Why? (113.) 



2. Explain the advantages of structure in a culm of wheat ; a stalk of 

 corn; arced. (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? (123.) 



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. Wliy are nurserymen, in grafting, so careful to make the cambium 

 layer of the graft hit that of the stock? (120.) 



12. In calculating 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 



Material. — 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, tropaolum, 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 loater 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 ? 



