LEAVES. 



87 



Notice that the leaf is traversed lengthwise by a strong midrib and 

 that many so-called veins run from this to the margin. Are these veins 

 parallel ? Hold the leaf up toward the light and see how the main veins 

 are connected by smaller veinlets. Examine with your glass the leaf as 

 held to the light and make a careful sketch of portions of one or two 

 veins and the intersecting veinlets. How is the course of the veins 

 shown on the upper surface of the leaf ? 



Fig. 66. — S b iUJ e s of 

 Margins of Leaves. 



a (1), finely serrate ; (2'), 

 coarsely serrate; (3), 

 doubly serrate, b (1), 

 finely dentate; [2), 

 sinuate dentate ; (3), 

 doubly dentate, c, 

 deeply sinuate, d, 

 wavy, e (1), crenate 

 or scalloped; (2), 

 doubly crenate. 



Fig. 67. — Netted Veining 

 (pinnate) in tlie Leaf of 

 tbe Foxglove. 



Examine both surfaces of the leaf with the glass and look for hairs 

 distributed on the surfaces. Describe the manner in wiiich the hairs are 

 arranged. 



The various forms of leaves are classed and described by- 

 botanists vs^ith great minuteness,^ not simply for the study of 



' See Kerner and Oliver's Xatural History of Plants, vol. I, pp. 623-637. 



