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

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 2.

4. Staminate flowering branchlet, 1/2.

5. Staminate flower, enlarged.

6. Pistillate flowering branchlet, 1/2.

7. Pistillate flower, enlarged.

8. Fruit, 1/2.]

+SALICACEAE+

+White Poplar+

_Populus alba L._

HABIT.--A large tree 60-80 feet high, with a trunk diameter of 2-4 feet, forming a large, spreading, rounded or irregular crown of large, crooked branches and spa.r.s.e, stout branchlets.

LEAVES.--Alternate, simple, 2-4 inches long and almost as broad; broadly ovate to suborbicular; irregularly toothed, sinuate, or sometimes 3-5-lobed; glabrous, dark green above, white-tomentose to glabrous beneath; petioles long, slender, flattened, tomentose.

FLOWERS.--April-May, before the leaves; dioecious; the staminate catkins thick, cylindrical, 2-4 inches long; the pistillate catkins slender, 1-2 inches long; calyx 0; corolla 0; stamens 6-16, with purple anthers; stigmas 2, branched, yellow.

FRUIT.--May-June; ovoid, 2-valved capsules, 1/8-1/4 inch long, borne in drooping catkins 2-4 inches long; seeds light brown, surrounded by long, white hairs.

WINTER-BUDS.--Ovoid, pointed, not viscid, downy, about 1/4 inch long.

BARK.--Twigs greenish, covered with a white down, becoming greenish gray and marked with darker blotches; dark gray and fissured at the base of old trunks.

WOOD.--Light, soft, weak, difficult to split, reddish yellow, with thick, whitish sapwood.

NOTES.--A native of Europe and Asia. Hardy in Michigan. Grows rapidly in good soils; thrives in poor soils and exposed situations. Roots deep, producing numerous suckers for a considerable distance from the tree.

[Ill.u.s.tration: +Aspen+

1. Winter twig, 2.

2. Leaf, 1.

3. Staminate flowering branchlet, 1/2.

4. Staminate flower, enlarged.

5. Pistillate flowering branchlet, 1/2.

6. Pistillate flower, enlarged.

7. Fruit, 1/2.]

+SALICACEAE+

+Aspen+

_Populus tremuloides Michx._

HABIT.--A small, slender tree generally 35-45 feet high, with a trunk diameter of 8-15 inches; forming a loose, rounded crown of slender branches.

LEAVES.--Alternate, simple, 1-1/2-2-1/2 inches long and broad; broadly ovate to suborbicular; finely serrate; thin and firm; l.u.s.trous, dark green above, dull and pale beneath; petioles slender, laterally compressed. Tremulous with the slightest breeze.

FLOWERS.--April, before the leaves; dioecious; the staminate catkins 1-1/2-3 inches long, the pistillate at first about the same length, gradually elongating; calyx 0; corolla 0; stamens 6-12; stigmas 2, 2-lobed, red.

FRUIT.--May-June; 2-valved, oblong-cylindrical, short-pedicelled capsules 1/4 inch long; seeds light brown, white-hairy.

WINTER-BUDS.--Terminal bud about 1/4 inch long, narrow-conical, acute, red-brown, l.u.s.trous; lateral buds often appressed.

BARK.--Twigs very l.u.s.trous, red-brown, becoming grayish and roughened by the elevated leaf-scars; thin, yellowish or greenish and smooth on the trunk, often roughened with darker, horizontal bands or wart-like excrescences, becoming thick and fissured, almost black at the base of old trunks.

WOOD.--Light, soft, weak, close-grained, not durable, light brown, with thin, whitish sapwood.

DISTRIBUTION.--Common throughout the state, but most abundant in the Upper Peninsula.

HABITAT.--Prefers moist, sandy soil and gravelly hillsides.

NOTES.--One of the first trees to cover burned-over lands. Grows rapidly.

Usually short-lived. Propagated from seed or cuttings.

[Ill.u.s.tration: +Largetooth Aspen+

1. Winter twig, 2.

2. Leaf, 1.

3. Staminate flowering branchlet, 1/2.

4. Staminate flower, enlarged.

5. Pistillate flowering branchlet, 1/2.

6. Pistillate flower, enlarged.

7. Fruit, 1/2.]

+SALICACEAE+

+Largetooth Aspen+

_Populus grandidentata Michx._

HABIT.--A medium-sized tree 30-50 feet high, with a slender trunk 12-20 inches in diameter; forming a loose, oval or rounded crown of slender, spreading branches and coa.r.s.e spray.

LEAVES.--Alternate, simple, 3-5 inches long, two-thirds as broad; orbicular-ovate; coa.r.s.ely and irregularly sinuate-toothed; thin and firm; dark green above, paler beneath, glabrous both sides; petioles long, slender, laterally compressed.

FLOWERS.--April, before the leaves; dioecious; the staminate in short-stalked catkins 1-3 inches long; the pistillate in loose-flowered, long-stalked catkins at first about the same length, but gradually elongating; calyx 0; corolla 0; stamens 6-12, with red anthers; stigmas 2, 2-lobed, red.