32 REPRESENTATIVE PLANTS 



Exp. 14. The effect of wind pressure and means of re- 

 sistance. (Instructor.) 



Exp. 15. Effect of climatic extremes on bark character. 



(Instructor.) 



Exp. 16. Grafting. (Students or instructor.) 



Exp. 17. Budding. (Students or instructor.) 



Exp. 18. Cuttings, stolons, layers. (Students or in- 

 structor.) 



Exp. 19. Pruning. (Instructor.) 



The above list is largely suggestive. The experiment 

 details may be stated more fully as the instructor desires. 

 Other experiments not named may be given. 



SECTION V. LEAVES 

 1. Geranium Leaves or other Complete Leaf 



General statement. When the study of leaves comes 

 during the "off'" season, there is no better form to be easily 

 obtained than the geranium. During the growing season 

 many other leaves may be added to the list, but even at 

 such time it will be difficult to improve on this selection. 

 The pupil should compare all available leaf forms, in order 

 to broaden his comprehension of these most vital parts of 

 the plant. 



Surface features. Examine a growing shoot of a geranium 

 and observe the leaves borne here and there. What is tlieir 

 variations in size on different parts of the shoot? Where 

 are they largest and why ? A leaf has the following parts : 

 If it is a complete leaf, it will have a pair of small, expanded 

 structures, stipules, where the leafstalk joins the shoot ; 

 a petiole or leafstalk, bearing at its outer or distal end the 

 large green expanded blade. Are all these parts found in 

 the geranium? Observe that the blade is supported upon 

 a framework of ribs or veins. When one main vein runs 



