TRANSFORMATIONS OF LEAVES 6 1 



I 



In any undisturbed forest tract turn up a few inches of soil with a gar- 

 den trowel and see what it is composed of. Notice what kind of plants 

 grow in it. Note the absence of weeds and account for it. Compare 

 the appearance of trees scattered along windy hillsides, where the fallen 

 leaves are constantly blown away, or in any position where the soil is 

 unrenewed, with those in an undisturbed forest, and then give an 

 opinion as to the wisdom of hauling away the leaves every year from a 

 timber lot. 



Sections 31-49. Observe the effect of the lobing and branching of 

 leaves in letting the sunlight through. Notice any general differences 

 that may appear as to shape, margin, and texture in the leaves of sun 

 plants, shade plants, and water plants, and account for them. Study the 

 arrangement of leaves on stems of various kinds and see how it is 

 adapted in each case to the shape of the foliage. Consider the value 

 of the various kinds of foliage for shade ; for ornament ; as producers 

 of moisture ; as food ; as insect destroyers, etc. 



It is important to learn to know and distinguish the different kinds of 

 trees and shrubs in your neighborhood by their leaves. A useful exer- 

 cise for this purpose is to make a collection of those of some family like 

 the oaks or hawthorns, that contains a great many varieties, and com- 

 pare them carefully with one another. 



Sections 50-65. In different mosaics and rosettes of leaves study 

 the means by which the adjustment has been brought about and the 

 purpose it subserves. Notice the form and position of petioles of 

 different leaves, and their effect upon light exposure, drainage, etc., and 

 the behavior of the different kinds in the wind. Look for compass 

 plants in your neighborhood, and for other examples of adjustment to 

 heat and light. Study the position of leaves at different times of day 

 and in different kinds of weather and note what changes occur arid to 

 what they are due. The sunflower and pea families offer some of the 

 most striking examples of this kind of sensitiveness. The oxalis and 

 geraniums, cotton, and others of the mallow family ought also to be 

 investigated. 



Study the drainage system of different plants and observe whether 

 there is any general correspondence between the leaf drainage and the 

 root systems. This will lead to interesting questions in regard to irri- 

 gation and manuring. (Where plants are crowded the growth of both 

 roots and leaves is complicated with so many other factors that it is 

 best to select for observations of this sort specimens growing in more 

 or less isolated situations.) 



Notice the time of the expansion and shedding of the leaves of differ- 

 ent plants, and whether the early leafers, as a general thing, shed early 

 or late ; in other words, whether there seems to be any general time 

 relation between the two acts of leaf expansion and leaf fall. 



Sections 66-72. Look for instances of protected leaves ; study the 



