2. Sterile flower.

3. Stamen with pollen-sacs.

4. Fertile flower.

5. Fruiting branch.

6. Branch.

7. Branch with needle-shaped leaves.

SALICACEae. WILLOW FAMILY.

Trees or shrubs; leaves simple, alternate, undivided, with stipules either minute and soon falling or leafy and persistent; inflorescence from axillary buds of the preceding season, appearing with or before the leaves, in nearly erect, spreading or drooping catkins, sterile and fertile on separate trees; flowers one to each bract, without calyx or corolla; stamens one to many; style short or none; stigmas 2, entire or 2-4-lobed; fruit a 2-4-celled capsule.

POPULUS.

Inflorescence usually appearing before the leaves; flowers with lacerate bracts, disk cup-shaped and oblique-edged, at least in sterile flowers; stamens usually many, filaments distinct; stigmas mostly divided, elongated or spreading.

SALIX.

Inflorescence appearing with or before the leaves; flowers with entire bracts and one or two small glands; disks wanting; stamens few.

=Populus tremuloides, Michx.=

POPLAR. ASPEN.

=Habitat and Range.=--In all soils and situations except in deep swamps, though more usual in dry uplands; sometimes springing up in great abundance in clearings or upon burnt lands.

Newfoundland, Labrador, and Nova Scotia to the Hudson bay region and Alaska.

New England,--common, reaching in the White mountain region an alt.i.tude of 3000 feet.

South to New Jersey, along the mountains in Pennsylvania and Kentucky, ascending 3000 feet in the Adirondacks; west to the slopes of the Rocky mountains, along which it extends to Mexico and Lower California.

=Habit.=--A graceful tree, ordinarily 35-40 feet and not uncommonly 50-60 feet high; trunk 8-15 inches in diameter, tapering, surmounted by a very open, irregular head of small, spreading branches; spray spa.r.s.e, consisting of short, stout, leafy rounded shoots set at a wide angle; distinguished by the slenderness of its habit, the light color of trunk and branches, the deep red of the sterile catkins in early spring, and the almost ceaseless flutter of the delicate foliage.

=Bark.=--Trunk pale green, smooth, dark-blotched below the branches, becoming ash-gray and roughish in old trees; season's shoots dark reddish-brown or green, shining; bitter.

=Winter Buds and Leaves.=--Buds 1/8-1/4 inch long, reddish-brown and l.u.s.trous, usually smooth, ovate, acute, often slightly incurved at apex, the upper often appressed. Leaves 1-2-1/2 inches long, breadth usually equal to or exceeding the length, yellowish-green and ciliate when young, dark dull green above when mature, lighter beneath, glabrous on both sides, bright yellow in autumn; outline broadly ovate to orbicular, finely serrate or wavy-edged, with incurved, glandular-tipped teeth, apex rather abruptly acute or short-ac.u.minate; base acute, truncate or slightly heart-shaped, 3-nerved; leafstalk slender, strongly flattened at right angles to the plane of the blade, bending to the slightest breath of air; stipules lanceolate, silky, soon falling.

=Inflorescence.=--April to May. Sterile catkins 1-3 inches long, fertile at first about the same length, gradually elongating; bracts cut into several lanceolate or linear divisions, silky-hairy; stamens about 10; anthers red: ovary short-stalked; stigmas two, 2-lobed, red.

=Fruit.=--June. Capsules, in elongated catkins, conical; seeds numerous, white-hairy.

=Horticultural Value.=--Hardy throughout New England in the most exposed situations; grows almost anywhere, but prefers a moist, rich loam; grows rapidly; foliage and spray thin; generally short-lived; often used as a screen for slow-growing trees; type seldom found in nurseries, but one or two horticultural forms are occasionally offered. Propagated from seed or cuttings.

[Ill.u.s.tration: PLATE XIV.--Populus tremuloides.]

1. Branch with sterile catkins.

2. Sterile flower.

3. Branch with fertile catkins.

4. Fertile flower.

5. Fruiting branch.

6. Branch with mature leaves.

7. Variant leaves.

=Populus grandidentata, Michx.=

POPLAR. LARGE-TOOTHED ASPEN.

=Habitat and Range.=--In rich or poor soils; woods, hillsides, borders of streams.

Nova Scotia, New Brunswick, southern Quebec, and Ontario.

New England,--common, occasional at alt.i.tudes of 2000 feet or more.

South to Pennsylvania and Delaware, along the mountains to Kentucky, North Carolina, and Tennessee; west to Minnesota.

=Habit.=--A tree 30-45 feet in height and 1 foot to 20 inches in diameter at the ground, sometimes attaining much greater dimensions; trunk erect, with an open, unsymmetrical, straggling head; branches distant, small and crooked; branchlets round; spray spa.r.s.e, consisting of short, stout, leafy shoots; in time and manner of blossoming, constant motion of foliage, and general habit, closely resembling _P.

tremuloides._

=Bark.=--Bark of trunk on old trees dark grayish-brown or blackish, irregularly furrowed, broad-ridged, the outer portions separated into small, thickish scales; trunk of young trees soft greenish-gray; branches greenish-gray, darker on the underside; branchlets dark greenish-gray, roughened with leaf-scars; season's twigs in fall dark reddish-brown, at first tomentose, becoming smooth and shining.

=Winter Buds and Leaves.=--Buds 1/8 inch long, mostly divergent, light chestnut, more or less p.u.b.escent, dusty-looking, ovate, acute. Leaves 3-5 inches long, two-thirds as wide, densely white-tomentose when opening, usually smooth on both sides when mature, dark green above, lighter beneath, bright yellow in autumn; outline roundish-ovate, coa.r.s.ely and irregularly sinuate-toothed; teeth acutish; sinuses in shallow curves; apex acute; base truncate or slightly heart-shaped; leafstalks long, strongly flattened at right angles to the plane of the blade; stipules thread-like, soon falling.

=Inflorescence.=--March to April. Sterile catkins 1-3 inches long, fertile at first about the same length, but gradually elongating; bracts cut into several lanceolate divisions, silky-hairy; stamens about 10; anthers red: ovaries short-stalked; stigmas two, 2-lobed, red.

=Fruit.=--Fruiting catkins at length 3-6 inches long; capsule conical, acute, roughish-scurfy, hairy at tip: seeds numerous, hairy.

=Horticultural Value.=--Hardy throughout New England; grows almost anywhere, but prefers moist, rich loam; grows rapidly and is safely transplanted, but is unsymmetrical, easily broken by the wind, and short-lived; seldom offered by nurserymen, but readily procured from northern collectors of native plants. Useful to grow for temporary effect with permanent trees, as it will fail by the time the desirable kinds are well established. Propagated from seed or cuttings.

=Note.=--Points of difference between _P. tremuloides_ and _P.

grandidentata_. These trees may be best distinguished in early spring by the color of the unfolding leaves. In the sunlight the head of _P.

tremuloides_ appears yellowish-green, while that of _P. grandidentata_ is conspicuously cotton white. The leaves of _P. grandidentata_ are larger and more coa.r.s.ely toothed, and the main branches go off usually at a broader angle. The buds of _P. grandidentata_ are mostly divergent, dusty-looking, dull; of _P. tremuloides_, mostly appressed, highly polished with a resinous l.u.s.tre.

[Ill.u.s.tration: PLATE XV.--Populus grandidentata.]

1. Branch with sterile catkins.

2. Sterile flower, back view, 3. Sterile flower, front view.

4. Branch with fertile catkins.

5. Bract of fertile flower.

6. Fertile flower, front view.

7. Fruiting branch with mature leaves.

8. Fruit.

9. Fruit.