KEY FOR THE IDENTIFICATION OF TREES AND SHRUBS 45 



small incurved marginal teeth, 

 crushed leaves with bitter 

 odor. .Black Cherry 



Prunus serotlna Ehrh. 

 21. As above but leaf shorter and 

 broader, elliptic or obovate, 

 sharply serrate. 



Cultivated Cherry 

 Prunus Cerasus L. 

 21. Leaf lanceolate, tapering to 

 both ends, 4-7 inches long, 

 margin often wavy, with short, 

 sharp-pointed teeth. 

 Peach 



Prunus Perslca (L. ) 

 Stokes 

 21. Tiny black glands on upper 

 side of petiole and on upper 

 surface of blade. Bark white 

 with triangular black mark- 

 ings below the branches. 

 Grey Birch 



Betula poduI i fo Ha Marsh. 

 21. Glands on edge of petiole, 

 leaf broad-lanceolate, shin- 

 ing, See #18 



Salix pentandra L. 

 22. Leaf approximately triangular, 

 ovate with a more or less 

 straight base,' margin toothed. 



Genus Povulus 2J> 



22. Leaf ovate-elliptic, sharply 

 toothed or lobed. 



Genus Crataegus. ... 25 

 22. Leaf large, orbicular in 

 general outline but deeply 



3 or 5 lobed 26 



22. Leaf large, long-elliptic, 



serrate or lobed 29 



25. Leaf stalk laterally com- 

 pressed just below the 



blade 24 



23. Leaf stalk not compressed 

 but rounded, leaf white- 

 downy beneath, margin 



