100 



LEAVES AND FOLIAGE 



148. Two pairs of connate leaves 

 of honeysuckle. 



m 



% 



each kind of leaf. The margin is entire when it is not indented 

 or cut in any way (Fig. 149). When not entire, it may be 

 undulate or wavy (Fig. 140), ser- 

 rate or saw-toothed (Fig. 152), 

 dentate or more coarsely notched 

 (Fig. 138), crenate or 

 round-toothed, lobed, 

 and other forms. 



213. Leaves often 

 differ greatly in shape 

 on the same plant. 

 Observe the different 

 shapes of leaves on the 

 young growths of mul- 

 berries (Fig. 88) and 

 wild grapes; also on vigorous squash and pumpkin 

 vines. In some cases there may be simple and com- 

 pound leaves on the same plant. This is marked 

 in the so-called Boston ivy or ampelopsis (Fig. 155), 

 a vine which is used to 

 cover brick and stone build- 

 ings. Different degrees of 

 compounding, even in the 

 same leaf, may often be 

 found in honey-locust and 

 Kentucky coffee tree. Re- 

 markable differences in 

 forms are seen by com- 

 paring seed-leaves with mature leaves 

 of any plant (Fig. 156). 



214. The Leaf and Its Environ- 

 ment. — The form and shape of the 

 leaf often have direct relation to the place in which the 

 leaf grows. Floating leaves are usually expanded and flat, 

 and the petiole varies in length with the depth of the water. 



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f 7 ) 



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7 



J 



V 



150. Linear- 

 acuminate 

 leaf of 

 grass. 



[g:3 



149. 



Short-oblong leaves of box. 



