+WINTER KEY TO THE SPECIES OF PICEA+

a. Leaves 3/4-1 inch long, sharp pointed; twigs glabrous.

b. Cones 1-2 inches long, maturing in first season; leaves ill-scented when bruised. _P. canadensis_, p. 21.

bb. Cones 3-6 inches long, maturing in second season; leaves not ill-scented when bruised. _P. abies_, p. 25.

aa. Leaves 1/8-3/8 inch long, blunt-pointed; twigs rusty-p.u.b.escent. _P. mariana_, p. 23.

[Ill.u.s.tration: +White Spruce+

1. Winter branchlet, x.

2. Leaves, 1.

3. Cross-section of leaf, enlarged.

4. Unopened cone, 1.

5. Partly opened cone, 1.

6. Cone-scale with seeds, 1.]

+PINACEAE+

+White Spruce+

_Picea canadensis (Mill.) BSP._ [_Picea alba Link_]

HABIT.--A tree 50-60 feet high, with a trunk diameter of 1-2 feet; forming a rather broad, open, pyramidal crown.

LEAVES.--Spirally arranged, but crowded on the upper side of the branches by the twisting of those on the under side; awl-shaped, 4-sided, incurved; dark blue-green; about 3/4 inch long; ill-scented when bruised. Persistent for several years.

FLOWERS.--April-May; monoecious; the staminate oblong-cylindrical, long-stalked, 1/2-3/4 inch long, composed of many spirally arranged, red anthers; the pistillate oblong-cylindrical, composed of broad, reddish scales (subtended by orbicular bracts) spirally arranged upon a central axis.

FRUIT.--Autumn or early winter of first season, falling soon after discharging the seeds; pendent, slender, oblong-cylindrical, nearly sessile cones, 1-2 inches long; seeds about 1/8 inch long, with large wings oblique at the apex.

WINTER-BUDS.--Broadly ovoid, obtuse, light brown, 1/8-1/4 inch long.

BARK.--Twigs smooth, gray-green, becoming orange-brown, finally dark gray-brown; thin, light gray-brown on the trunk, separating into thin, plate-like scales.

WOOD.--Light, soft, weak, straight-grained, light yellow, with sapwood of the same color.

DISTRIBUTION.--Common in the northern half of the Lower Peninsula and throughout the Upper Peninsula.

HABITAT.--Low, damp woods; banks of streams; borders of lakes; high rocky or sandy slopes; loves the cold winters.

NOTES.--A vigorous and beautiful tree in regions sufficiently cold.

[Ill.u.s.tration: +Black Spruce+

1. Winter branchlet, 1.

2. Leaves, 2.

3. Cross-sections of leaves, enlarged.

4-5. Opened cones, 1.

6. Cone-scale with seeds, 1.]

+PINACEAE+

+Black Spruce+

_Picea mariana (Mill.) BSP._ [_Picea nigra Link_]

HABIT.--A small tree 20-30 feet high, with a trunk diameter of 6-10 inches; forming a narrow-based, conical, more or less irregular crown of short, slender, horizontal branches; often small and stunted.

LEAVES.--Spirally arranged, spreading in all directions; awl-shaped, 4-sided, blunt at the apex, more or less incurved; stiff; dark blue-green and glaucous; 1/8-3/8 inch long. Persistent for several years.

FLOWERS.--April-May; monoecious; the staminate subglobose, about 1/2 inch long, composed of many spirally arranged, dark red anthers; the pistillate oblong-cylindrical, composed of broad, purple scales (subtended by rounded, toothed, purple bracts) spirally arranged upon a central axis, about 1/2 inch long.

FRUIT.--Autumn of first season, but persistent on the branch for many years; pendent, ovoid, short-stalked cones, about 1 inch long; seeds about 1/8 inch long, with pale brown wings 1/2 inch long.

WINTER-BUDS.--Ovoid, acute, light red-brown, p.u.b.erulous, 1/8 inch long.

BARK.--Twigs at first green and rusty-p.u.b.escent, becoming dull red-brown and rusty-p.u.b.escent; thin, gray-brown on the trunk, separating into thin, appressed scales.

WOOD.--Light, soft, weak, pale yellow-white, with thin, pure white sapwood.

DISTRIBUTION.--Occurs sparingly in southern Michigan; more abundant in the northern portions.

HABITAT.--Cold, sphagnous bogs and swamps; sh.o.r.es of lakes.

NOTES.--Short-lived. Undesirable for ornamental planting. Growing to its largest size in the far north.

[Ill.u.s.tration: +Norway Spruce+

1. Branchlet with partly opened cone, 1/2.

2. Leaf, 3.

3. Cross-sections of leaves, enlarged.

4. Cone-scale with seeds, 1.]

+PINACEAE+

+Norway Spruce+

_Picea abies (L.) Karst._ [_Picea excelsa Link_]