WINTER KEY TO THE SPECIES OF 
FRAXINUS 
a. Twigs prominently 4-angled; fruit falling in early autumn 
SAAR cee AALS WSs aes F. quadrangulata, p. 219. 
aa. Twigs terete; fruit often persistent on the tree until mid- 
winter or the following spring. 
b. Buds rusty-tomentose; twigs more or less downy........ 
we dae hA-aaus SARA OR F, pennsylvanica, p. 215. 
bb. Buds not tomentose; twigs not downy. 
c. Terminal bud black or nearly so, showing 3 pairs of 
scales in cross-section; bud-scales apiculate at the apex; 
samaras with broad wings, the seed portion flattish; 
bark flaky, rubbing off on the hand..... F. nigra, p. 221. 
cce.. Terminal bud brownish, showing 4 pairs of scales in 
cross-section; bud-scales rounded at the apex; samaras 
with narrow wings, the seed portion terete; bark ridged, 
not flaky and rubbing off on the hand. 
d. Upper margin of leaf-scars deeply concave.......... 
a RAe aR iG gate ore Samael F. americana, p. 213. 
dd. Upper margin of leaf-scars not concave, but straight 
across or projecting upward...............ccceeeeee 
ide taeas eee F, pennsylvanica lanceolata, p. 217. 
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