THE LEAF. 57 



V. THE LEAF. 



MATERIAL KEQUIEED. 



Leaves of as many kinds as are procurable. See suggestions under 

 "Systematic Description." Branches of basswood, elm, maple, 

 and horse-chestnut. Leafy plants of primrose, fuchsia, dandelion, 

 and geranium. 



Leaves of hyacinth and English ivy. 



Leaves of various hairy plants and of conifers, rushes and sedges, etc. 



Leaves of different ferns and flowering plants called for under "Me- 

 chanical and Conducting System." 



Specimens of Elodea Canadensis growing in water, and of Mnium or 

 other common moss. 



Tropaeolum and other convenient plants growing in pots 



A collection of modified leaves. 



SYSTEMATIC DESCRIPTION. 



Write a careful and complete description of the leaves 

 of ten or a dozen different plants, following, as far as it 

 proves serviceable, the schedule given below. 



Some one has said that " there is no part of botany so 

 overwhelmed with cumbrous terminology as that which 

 relates to leaves." Nevertheless the really necessary 

 terms are easily learned, and the peculiarities expressed 

 by them are far from accidental. The form of the leaf, its 

 position on the stem, the venation and other structural 

 features are generally such as to secure the greatest effi- 

 ciency, and in studying these it is desirable to be able 

 to express one's self with exactness. The greenhouse or 



