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. 181. 



dd. Buds hoary-pubescent; bark sometimes almost black 



on the trunk A. saccharum nigrum, p. 183. 



aa. Terminal buds usually ^4~H inch in length, 

 b. Buds reddish; opposite leaf-scars meeting. 



c. Buds conspicuously stalked; bud-scales visible, I pair; 

 bark longitudinally white-striped; small tree or large 



shrub A. pennsylvanicum, p. 177. 



cc. Buds not conspicuously stalked; bud-scales visible, 2-3 



pairs ; bark not white-striped ; large tree 



A. platanoides, p. 189. 



bb. Buds bright green; opposite leaf-scars not meeting...... 



A. pseudo-platanus, p. 191. 



175 



