WINTER KEY TO THE SPECIES OF ACER 



a. Terminal buds usually under J4 inch in length, 

 b. Buds white-woolly ; twigs usually with a whitish bloom ; 

 opposite leaf-scars meeting; fruit often persistent on the 



tree until spring A. negundo, p. 193. 



bb. Buds not white-woolly; twigs without whitish bloom; 

 opposite leaf-scars not meeting; fruit not persistent on 

 the tree in winter, 

 c. Buds reddish or greenish ; twigs bright red. 



d. Twigs strictly glabrous; buds glabrous; spherical 

 flower buds clustered on the sides of the shoot; pith 

 pink ; large trees. 



e. Twigs rank-smelling when broken; tip of outer 

 bud-scales often apiculate; tips of branches curving 

 upwards; bark separating into long, thin flakes 



loose at the ends A. saccharinum, p. 185. 



ee. Twigs not rank-smelling when broken; tip of outer 

 bud-scales rounded; tips of branches not conspic- 

 uously curving upwards; bark rough-ridged, but 



seldom forming loose flakes A. rubrum, p. 187. 



dd. Twigs appressed-'hairy, at least near ithe tip ; buds 

 somewhat tomentose; spherical flower buds absent; 



pith brown; shrub or bushy tree.. A. spicatum, p. 179. 

 174 



