88 



ELEMENTS OP BOTANY. 



leaves themselves, but also because in classifying and describ- 

 ing plants the characteristic forms of the leaves of many 

 kinds of plants form a very simple and ready means of dis- 

 tinguishing them from each other and identifying them. The 

 student is not expected to learn the names of the several 

 shapes of leaves as a whole or of their bases, tips, or margins, 

 except in those cases in which he needs to use and apply 

 them. 



1 16. The Maple Leaf.^ — Sketch 

 the leafy twig. 



Are the leaves arranged in rows 

 like those of the elm ? How are they 

 arranged ? 



Fig. 68. — Palmately Netted-Veined 

 Leaf of Melon. 



Fig. 69. — Pinnately Divided 

 Leaf of Celandine. 

 The Wade of the leaf Is 

 discontinuous, consisting of 

 several portions bet we; en 

 which are spaces in which no 

 part of the blade has been 

 developed. 



Notice the way in which half of the whole number of petioles are 

 tvfisted and some of the others bent to bring the proper surface of the 

 leaf upward toward the light. 



Do the edges of these leaves show larger spaces between them than 

 the elm leaves did, i.e., would a spray of maple intercept the sunlight 



1 Any kind of maple will answer the purpose. Palmately veined leaves are less 

 abundant among our forest trees than are pinnately veined ones. The sycamore is 

 one of the commonest species. Among other plants may be suggested the ordinary 

 " geraniums " (pelargoniums), the pumpkin, squash, grape, currant, and hollyhock. 



