OLEACEAE

SUMMER KEY TO THE SPECIES OF FRAXINUS

a.Lateral leaflets sessile.F. nigra, p. [221].
aa.Lateral leaflets petioluled.
b.Twigs, petioles and lower sides of leaves pubescent.F. pennsylvanica, p. [215].
bb.Twigs, petioles and lower sides of leaves essentially glabrous.
c.Twigs prominently 4-angled.F. quadrangulata, p. [219].
cc.Twigs terete.
d.Lower sides of leaves essentially of the same coloras the upper; leaflet-margins rather finely sharp-serrate.F. pennsylvanica lanceolata, p. [217].
dd.Lower sides of leaves paler than the upper; leaflet-marginsentire or obscurely serrate.F. americana, p. [213].

WINTER KEY TO THE SPECIES OF FRAXINUS

a.Twigs prominently 4-angled; fruit falling in early autumn.F. quadrangulata, p. [219].
aa.Twigs terete; fruit often persistent on the tree until mid-winteror the following spring.
b.Buds rusty-tomentose; twigs more or less downy.F. pennsylvanica, p. [215].
bb.Buds not tomentose; twigs not downy.
c.Terminal bud black or nearly so, showing 3 pairs ofscales 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].
cc.Terminal bud brownish, showing 4 pairs of scales incross-section; bud-scales rounded at the apex; samaraswith narrow wings, the seed portion terete; bark ridged,not flaky and rubbing off on the hand.
d.Upper margin of leaf-scars deeply concave.F. americana, p. [213].
dd.Upper margin of leaf-scars not concave, but straightacross or projecting upward.F. pennsylvanica lanceolata, p. [217].