Michigan Trees Part 21

_Carpinus caroliniana Walt._

HABIT.--Usually a low, bushy tree or large shrub, 10-30 feet high, with a trunk diameter of 6-12 inches; trunk short, usually fluted; slender zigzag branches and a fine spray form a close, flat-topped crown.

LEAVES.--Alternate, simple, 2-4 inches long and one-half as broad; ovate to oval, long-pointed; sharply doubly serrate; thin and firm; dull green above, lighter beneath, turning scarlet and orange in autumn; petioles short, slender, hairy.

FLOWERS.--May, after the leaves; monoecious; apetalous; the staminate catkins 1-1-1/2 inches long, their scales greenish, boat-shaped, each bearing 3-20 stamens; the pistillate catkins 1/2-3/4 inch long, their scales hairy, greenish, each bearing 2 pistils with long, scarlet styles.

FRUIT.--Ripens in midsummer, but often remains on the tree long after the leaves have fallen; in loose, terminal strobiles; involucre halberd-shaped, inclosing a small, ovate, brownish nut.

WINTER-BUDS.--Terminal bud absent; lateral buds 1/8 inch long, narrow-ovoid, acute, p.u.b.erulous, brownish.

BARK.--Twigs pale green, hairy, becoming l.u.s.trous, dark red the first winter; trunk and large limbs thin, smooth, close, dark bluish gray, often mottled with lighter or darker patches.

WOOD.--Heavy, hard, tough, very strong, close-grained, light brown, with thick, whitish sapwood.

DISTRIBUTION.--Common throughout the state.

HABITAT.--Prefers a deep, rich, moist soil along the borders of streams and swamps. Often found in drier situations in the shade of other trees.

NOTES.--Propagated from seed. Not easily transplanted. Slow of growth.

Seldom found in ma.s.ses.

+SUMMER KEY TO THE SPECIES OF BETULA+

a. Bark of trunk white, separating freely into thin, papery layers; twigs without wintergreen taste; leaves usually solitary, not aromatic. _B. alba papyrifera_, p. 91.

aa. Bark of trunk not white, usually dark colored, not separating freely into papery layers; twigs with more or less wintergreen taste; leaves solitary or in pairs, aromatic.

b. Bark dirty-yellow, breaking into strips more or less curled at the edges; leaves solitary or in pairs, slightly aromatic; twigs with slight wintergreen taste. _B. lutea_, p. 89.

bb. Bark dark red-brown, cleaving off in thick, irregular plates (resembles bark of Black Cherry); leaves in pairs, strongly aromatic; twigs with strong wintergreen taste. _B.

lenta_, p. 87.

+WINTER KEY TO THE SPECIES OF BETULA+

a. Bark of trunk white, separating freely into thin, papery layers; twigs without wintergreen taste. _B. alba papyrifera_, p. 91.

aa. Bark of trunk not white, usually dark colored, not separating into papery layers; twigs with more or less wintergreen taste.

b. Bark dirty-yellow, breaking into strips more or less curled at the edges; twigs with slight wintergreen taste. _B. lutea_, p. 89.

bb. Bark dark red-brown, cleaving off in thick, irregular plates (resembles bark of Black Cherry); twigs with strong wintergreen taste. _B. lenta_, p. 87

[Ill.u.s.tration: +Sweet Birch. Black Birch. Cherry Birch+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 1/2.

4. Flowering branchlet, 1/2.

5. Staminate flower, enlarged.

6. Pistillate flower, enlarged.

7. Fruiting branchlet, 1/2.

8. Fruit, enlarged.]

+BETULACEAE+

+Sweet Birch. Black Birch. Cherry Birch+

_Betula lenta L._[F]

HABIT.--A medium-sized tree 70-80 feet high, with a trunk diameter of 1-3 feet; slender, wide-spreading, pendulous branches, forming a narrow, rounded, open crown.

LEAVES.--Alternate in pairs, simple, 3-4 inches long and one-half as broad; outline variable, ovate to oblong-ovate; sharply doubly serrate, with slender, incurved teeth; dull, dark green above, light yellow-green beneath; petioles short, stout, hairy, deeply grooved above; aromatic.

FLOWERS.--April, before the leaves; monoecious; the staminate catkins 3-4 inches long, slender, pendent, yellowish; the pistillate catkins 1/2-3/4 inch long, erect or suberect, greenish.

FRUIT.--Ripens in autumn; sessile, glabrous, erect strobiles, 1-1-1/2 inches long and half as thick; scales glabrous; nuts slightly broader than their wings.

WINTER-BUDS.--Terminal bud absent; lateral buds about 1/4 inch long, conical, sharp-pointed, red-brown, divergent.

BARK.--Twigs light green, becoming l.u.s.trous, red-brown in their first winter; very dark on old trunks, cleaving off in thick, irregular plates. Resembles bark of Black Cherry. Inner bark aromatic, spicy.

WOOD.--Heavy, very hard and strong, close-grained, dark red-brown, with thin, lighter colored sapwood.

DISTRIBUTION.--Scattered throughout the state; rare in the south, more abundant and of larger size in the north.

HABITAT.--Grows in any situation, but prefers moist, rocky slopes and rich uplands.

NOTES.--Hardy throughout its range. Easily transplanted.

[Ill.u.s.tration: +Yellow Birch. Gray Birch+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 1/2.

4. Flowering branchlet, 1/2.

5. Staminate flower, enlarged.

6. Pistillate flower, enlarged.

7. Fruiting branchlet, 1/2.

8. Fruit, 10.]