nd Frem., from the mountain regions farther west,
has its leaves in ones and twos; when in ones, round and very rigid;
when in pairs, flat on the inner side; leaves on the young shoots
bluish, glaucous green, or silvery. This is probably only a variety of
P. edulis. The seeds of both are so large and nutritious that they are
extensively used for food by the Indians.

GENUS =94. PICEA.= (THE SPRUCES.)

Leaves evergreen, scattered (pointing in every direction),
needle-shaped, keeled above and below, thus making them somewhat
4-sided. Fertile catkins and cones terminal; cones maturing the first
year, pendulous; scales thin, without prickles, persistent, the cone
coming off the tree whole.

* Leaves very short, usually 1/4 to 1/2 in. long, obtuse 7, 8.

* Leaves usually 1/2 in. or more long, acute. (=A.=)

=A.= Cones over 3 in. long; cultivated. (=B.=)

=B.= Leaves dark green; large tree, common 3.

=B.= Leaves bright or pale green 4, 5, 6.

=A.= Cones 2 in. or less long; large native trees 1, 2.

[Illustration: P. nigra.]

1. =Picea nigra=, Link. (BLACK OR DOUBLE SPRUCE.) Leaves about 1/2 in.
long, erect, stiff, somewhat 4-sided, very dark green or whitish-gray;
branchlets pubescent. Cones persistent, 1 to 1 1/2 in. long, ovate or
ovate-oblong, changing from dark purple to dull reddish-brown; scales
very thin, roundish, with toothed or uneven edges. A conical-shaped
tree, 40 to 80 ft. high; wild in the North and along the Alleghanies;
often cultivated. Bark dark brown; branches horizontal; wood light
reddish.

Var. _rubra_ has larger, darker leaves, and larger, brighter-colored
cones.

[Illustration: P. alba.]

2. =Picea alba=, Link. (WHITE OR SINGLE SPRUCE.) Leaves 1/2 to 3/4 in.
long, rather slender, needle-shaped, sharp-pointed, incurved, pale- or
glaucous-green; branchlets smooth. Cones deciduous, 2 in. long,
oblong-cylindrical, with entire, thin-edged scales. Tree 25 to 100 ft.
high, of beautiful, compact, symmetrical growth when young, and such
light-colored foliage as to make it a fine species for cultivation.
Wild in the North, and cultivated throughout. There are varieties with
bluish-green (var. _caerulea_) and with golden (var. _aurea_) foliage in
cultivation.

[Illustration: P. excelsa.]

3. =Picea excelsa=, Link. (NORWAY SPRUCE.) Leaves 3/4 to 1 in. long,
rigid, curved, dark green. Cones 5 to 7 in. l