Part 22

cc. Buds and twigs not conspicuously white-downy; twigs usually red-brown.

d. Terminal buds about 1/8 inch long, puberulous, dusty-looking; lateral buds widely divergent; twigs rather coarse. P. grandidentata, p. 51.

dd. Terminal buds about 1/4 inch long, glabrous, lustrous; lateral buds more or less appressed; twigs rather slender. P. tremuloides, p. 49.

bb. Terminal buds 1/2-1 inch long, sticky-resinous.

c. Terminal buds about 1/2 inch long; buds not fragrant; twigs usually yellow, more or less strongly angled. P. deltoides, p. 57.

cc. Terminal buds nearly 1 inch long; buds fragrant; twigs usually red-brown and seldom strongly angled. P. balsamifera p. 53. P. candicans p. 55.

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 sparse, 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.

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; lustrous, 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, lustrous; lateral buds often appressed.

BARK.--Twigs very lustrous, 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.