CHAPTER V. 

 LEAVES. 



PROVIDING MATERIALS. 



Most of the observations on leaves are best made in the field or 

 upon materials freshly brought into the laboratory. If vegetation out 

 of doors is not sufficiently advanced to begin the study of leaves as 

 soon as the work on buds and stems has been completed, the study 

 of modified structures outlined in a following chapter might next be 

 taken up, and the study of leaves postponed until the right kind of 

 material can be obtained in abundance. 



OBSERVATIONS. 



In the study of leaves, make account by notes and draw- 

 ings of the following points : 



73. The form of the leaf and the character of its outline. 



74. The texture of the leaf and the character of the two 

 surfaces, whether rough, smooth, hairy, etc. 



75. The manner of attachment of the leaf to the stem; 

 namely, is it broad or narrow at the base ? Is the leaf 

 blade attached to the stem, or does a leaf stalk or petiole 

 intervene ? Are there lateral outgrowths at the base of 

 the leaf ? 



76. How does the leaf vary as it grows from the bud ? 

 Do the form and size of the leaf and the character of the 

 two surfaces vary materially ? Compare the color of leaves 

 which are just issuing from the bud with that of mature 

 leaves. 



77. How do the leaves vary in form, size, and outline 



75 



