The Trees of Vermont 163 



WINTER KEY TO THE SPECIES OF ACER 



a. Terminal buds usually under ^4 i'^^^h in length, not conspicuously 

 stalked ; bark not longitudinally white-striped. 



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. 177. 



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. 173. 

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

 scales rounded ; tips of branches not conspicuously curv- 

 ing upwards ; bark rough-ridged, but seldom forming 



loose flakes A. rubrum, p. 175. 



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. 167. 



cc. Buds brownish ; twigs brownish or grayish. 



d. Buds glabrous, or somewhat pubescent at the apex only ; 



bark dark gray on the trunk A. saccharum, p. 169. 



dd. Buds hoary-pubescent ; bark sometimes almost Ijlack on the 



trunk A. sacchanim nigrum, p. 171. 



oa. Terminal buds usually ^-3/2 inch in length, conspicuously stalked; 

 bark longitudinally white-striped. . .A. pennsylvanicum, p. 165. 



