u 



KEY TO GENERA AND SPECIES 



Fig. 21. Redbud. Fig. 22. Redbud. 



19. Leaves symmetrically heart-shaped, margins 

 entire. N. Y. southward and westward, also 

 cult. (Figs. 21, 22.) Redbud, Judas-tree, 

 Cercis canadensis L. 



19. Leaves unsymmetrically heart-shaped, margins 



toothed Linden, 198. 



20. Leaves broader than long, with strong angles 



or shallow indentations. Southern Me. 

 southward and westward. (Figs. 23, 24, 25.) 

 Buttonwood, Buttonball-tree, Plane-tree, 

 American Sycamore, Sycamore, Platanus 

 occidentalis L. 



20. Leaves longer than wide 21. 



21. Leaf length not twice the width. Juice milky 



22. 



21. Leaf length not twice the width. Juice not 

 milky. Base of blade unsymmetrical Lin- 

 den, 198. 



