WINTER KEY TO THE SPECIES OF ACER 
a. Terminal buds usually under 34 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................-.0005 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 the tip; buds 
somewhat tomentose; spherical flower buds absent; 
pith brown; shrub or bushy tree..A. spicatum, p. 179, 
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