10, 11.

=A.= Leaves an inch or less long 12.

* Cones 3 1/2 to 6 in. long. (=B.=)

=B.= Leaves 2 in. or more long, 2-ranked 9.

=B.= Leaves 1 in. or less long. (=C.=)

=C.= Leaves acute at tip 7, 8.

=C.= Leaves blunt or notched at tip. (=D.=)

=D.= Two-ranked 4.

=D.= Not 2-ranked 3.

* Cones 1 to 3 1/2 in. long. (=E.=)

=E.= Leaves an inch or more long 5, 6.

=E.= Leaves less than an inch long 1, 2.

[Illustration: A. balsamea.]

1. =Abies balsamea=, Mill. (COMMON BALSAM-FIR.) Leaves narrow, linear,
1/2 to 3/4 in. long, and much crowded, silvery beneath; those on the
horizontal branches spreading into 2 ranks. Bark yielding Canada balsam
from blisters. Cones erect, on spreading branches, 2 to 4 in. long and 1
in. thick, cylindric, violet-colored, with mucronate-pointed bracts
extending beyond the scales and not reflexed. Wild in cold, wet grounds;
20 to 45 ft. high, with numerous horizontal branches. Has been
cultivated quite extensively, although there are better Firs for
ornamental purposes.

[Illustration: A. Fraseri.]

2. =Abies Fraseri=, Lindl. (FRASER'S OR SOUTHERN BALSAM-FIR.) Leaves 1/2
to 3/4 in. long, somewhat 2-ranked, linear, flattened, obtuse, emarginate,
whitish beneath, the lower ones curved and the upper ones erect. Cones
oblong, 1 to 2 in. long, with sharp-pointed bracts half exserted and
reflexed. A rare, small tree, 30 to 40 ft. high, growing wild in the
mountains, from Virginia south. A hardy tree and handsome when young.

[Illustration: A. Nordmanniana.]

3. =Abies Nordmanniana=, Link. (NORDMANN'S SILVER FIR.) Leaves very
numerous, crowded, broad, linear, blunt or erose-dentate at the ends,
somewhat curved, of unequal length, 1 in. or less long, deep green above
and whitened beneath. Cones large, 5 in. long, ovate, erect, with very
obtuse scales; bracts exserted and recurved. A beautiful large tree, 50
to 80 ft. high, occasionally cultivated; with numerous horizontal
branches and smooth bark.

[Illustration: A. firma.]

4. =Abies firma=, S. and Z. (JAPAN SILVER FIR.) Leaves 3/4 to 1 in. long,
very closely 2-ranked, slightly twisted, linear, somewhat notched at the
end, s