SUMMER KEY TO THE SPECIES OF POPULUS
| a. | Leaf-petioles essentially terete. | ||||
| b. | Petioles and lower sides of leaves pubescent; leaves heart-shaped. | P. candicans, p. [55]. | |||
| bb. | Petioles and lower sides of leaves glabrous; leaves ovate-lanceolate. | P. balsamifera, p. [53]. | |||
| aa. | Leaf-petioles strongly flattened. | ||||
| b. | Petioles and lower sides of leaves tomentose; twigspubescent. | P. alba, p. [47]. | |||
| bb. | Petioles and lower sides of leaves glabrous; twigs glabrous. | ||||
| c. | Leaves distinctly deltoid in shape. | ||||
| d. | Leaves broader than they are long, abruptly acuminateat the apex; marginal teeth not conspicuously incurved;branches erect and more or less appressed tothe main stem, forming a narrow, spire-like crown. | P. nigra italica, p. [59]. | |||
| dd. | Leaves longer than they are broad, more or less taper-pointedat the apex; marginal teeth rather conspicuouslyincurved; branches spreading, forming a broadcrown. | P. deltoides, p. [57]. | |||
| cc. | Leaves ovate to nearly orbicular in shape. | ||||
| d. | Margin of leaves coarsely sinuate-toothed; leaves 3-5inches long. | P. grandidentata, p. [51]. | |||
| dd. | Margin of leaves finely serrate; leaves less than 3inches long. | P. tremuloides, p. [49]. | |||
WINTER KEY TO THE SPECIES OF POPULUS
| a. | Branches erect, more or less appressed to the main stem,forming a narrow, spire-like crown. | P. nigra italica, p. [59]. | |||
| aa. | Branches spreading, forming a broad crown. | ||||
| b. | Terminal buds 1/8-1/4 inch long, not resinous. | ||||
| c. | Buds and twigs more or less conspicuously white-downy;twigs green. | P. alba, p. [47]. | |||
| cc. | Buds and twigs not conspicuously white-downy; twigsusually red-brown. | ||||
| d. | Terminal buds about 1/8 inch long, puberulous, dusty-looking;lateral buds widely divergent; twigs rathercoarse. | P. grandidentata, p. [51]. | |||
| dd. | Terminal buds about 1/4 inch long, glabrous, lustrous;lateral buds more or less appressed; twigs ratherslender. | 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; twigsusually red-brown and seldom strongly angled. | P. balsamifera[E] p. [55]. P. candicans[E] p. [55]. | |||
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 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.
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; 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.
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.
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 coarse spray.
LEAVES.—Alternate, simple, 3-5 inches long, two-thirds as broad; orbicular-ovate; coarsely 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.
FRUIT.—May; 2-valved, conical, acute, hairy capsules 1/8 inch long, borne in drooping catkins 4-6 inches long; seeds minute, dark brown, hairy.
WINTER-BUDS.—Terminal bud 1/8 inch long, ovoid to conical, acute, light chestnut, puberulous, dusty-looking.
BARK.—Twigs greenish gray and at first hoary-tomentose, becoming lustrous, orange or red-brown and finally greenish gray; thick, dark red-brown or blackish at the base of old trunks, irregularly fissured, with broad, flat ridges.
WOOD.—Light, soft, weak, close-grained, light brown, with thin, whitish sapwood.
DISTRIBUTION.—A common tree in the northern portions of the Lower Peninsula, but rare in the Upper Peninsula.
HABITAT.—Prefers rich, moist, sandy soil; borders of swamps; river-banks; hillsides.
NOTES.—Grows rapidly in many soils. Easily transplanted. Short-lived. Useful for temporary effect. Propagated from seed or cuttings.
Balm of Gilead. Balsam
1. Winter twig, × 1.
2. Leaf, × 3/4.
3. Staminate flowering branchlet, × 1/2.
4. Staminate flower, enlarged.
5. Catkin of pistillate flower, × 1/2.
6. Pistillate flower, enlarged.
7. Fruit, × 1/2.
SALICACEAE
Balm of Gilead. Balsam
Populus balsamifera L.
HABIT.—A tree 60-75 feet high, with a trunk diameter of 1-3 feet; forming a rather narrow, open, pyramidal crown of few, slender, horizontal branches.
LEAVES.—Alternate, simple, 3-6 inches long, about one-half as broad; ovate to ovate-lanceolate; finely crenate-serrate; thin and firm; lustrous, dark green above, paler beneath; petioles 1-1/2 inches long, slender, terete, smooth.
FLOWERS.—April, before the leaves; dioecious; the staminate in long-stalked catkins 3-4 inches long; the pistillate in loose-flowered, long-stalked catkins 4-5 inches long; calyx 0; corolla 0; stamens 20-30, with bright red anthers; ovary short-stalked; stigmas 2, wavy-margined.
FRUIT.—May-June; 2-valved, ovoid, short-pedicelled capsules 1/4 inch long, borne in drooping catkins 4-6 inches long; seeds light brown, hairy.
WINTER-BUDS.—Terminal bud about 1 inch long, ovoid, long-pointed, brownish, resin-coated, sticky, fragrant.
BARK.—Twigs red-brown, becoming dark orange, finally green-gray; thick, grayish on old trunks, and shallowly fissured into broad, rounded ridges, often roughened by dark excrescences.
WOOD.—Light, soft, weak, close-grained, light red-brown, with thick, nearly white sapwood.
DISTRIBUTION.—Occurs throughout the entire state, but is more abundant and of greater size in the northern portions.
HABITAT.—Prefers river bottom-lands and borders of swamps.
NOTES.—Rapid in growth. Spreads from the roots. Most useful for shelter belts. Easily transplanted. Propagated from cuttings.
Hairy Balm of Gilead. Balsam
1. Winter twig, × 1.
2. Leaf, × 1/2.
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
Hairy Balm of Gilead. Balsam
Populus candicans Ait. [Populus balsamifera candicans (Ait.) Gray]
HABIT.—A tree 50-70 feet high, with a trunk diameter of 1-3 feet; more spreading branches than in P. balsamifera, forming a broader and more open crown.
LEAVES.—Resemble those of P. balsamifera, but more broadly heart-shaped and more coarsely serrate; more or less pubescent when young; petioles pubescent.
FLOWERS.—Similar to those of P. balsamifera.
FRUIT.—Similar to that of P. balsamifera.
WINTER-BUDS.—Terminal bud about 1 inch long, ovoid, long-pointed, dark red-brown, resinous throughout, viscid, very aromatic.
BARK.—Twigs reddish or olive-green, with occasional longitudinal gray lines, covered with a fragrant, gummy secretion, becoming gray-green; dark gray, rough, irregularly striate and firm on old trunks.
WOOD.—Resembles that of P. balsamifera, but is somewhat heavier.
DISTRIBUTION.—Indigenous to the northern portions of the state, but often cultivated and occasionally escaping in the southern portion.
HABITAT.—In a great variety of soils and situations.
NOTES.—Grows rapidly in all soils and situations. Suckers readily from the roots. Propagated from cuttings.
Cottonwood
1. Winter twig, × 1.
2. Leaf, × 1/2.
3. Staminate flowering branchlet, × 1/2.
4. Staminate flower, enlarged.
5. Pistillate catkin, × 1/2.
6. Pistillate flower, enlarged.
7. Fruit, × 1/2.
SALICACEAE
Cottonwood
Populus deltoides Marsh. [Populus monilifera Ait.]
HABIT.—A stately tree attaining a height of 70-90 feet and a trunk diameter of 3-5 feet; forming a spreading, open, symmetrical crown of massive, horizontal branches and stout, more or less angled branchlets.
LEAVES.—Alternate, simple, 3-6 inches long, nearly as broad; broadly deltoid-ovate; coarsely crenate-serrate above the entire base; thick and firm; lustrous, dark green above, paler beneath; petioles 2-3 inches long, slender, compressed laterally.
FLOWERS.—April-May, before the leaves; dioecious; the staminate in short-stalked, densely-flowered catkins 3-4 inches long; the pistillate in short-stalked, few-flowered catkins elongating to 6-8 inches; calyx 0; corolla 0; stamens very numerous, with red anthers; stigmas 3-4, spreading.
FRUIT.—May; 2-4-valved, short-stalked capsules, borne in drooping catkins 5-10 inches long; seeds light brown, densely cottony.
WINTER-BUDS.—Terminal bud 1/2 inch long, conical, acute, very resinous, shining, brownish.
BARK.—Twigs and young stems smooth, yellow-green; old trunks ashy gray, deeply divided into straight furrows with broad, rounded ridges.
WOOD.—Light, soft, weak, close-grained, dark brown, with thick, whitish sapwood; warps badly and is difficult to season.
DISTRIBUTION.—Entire Michigan; rare in the northern portions.
HABITAT.—Prefers rich, moist soil; river-banks; river-bottoms; lake-shores; grows well in drier situations.
NOTES.—Rapid of growth, consequently an excellent tree for immediate effect. Propagated from cuttings.
Lombardy Poplar
1. Winter twig, × 1.
2. Portion of twig, enlarged.
3. Leaf, × 3/4.
4. Staminate flowering branchlet, × 1/2.
5. Staminate flower, enlarged.
SALICACEAE
Lombardy Poplar
Populus nigra italica DuRoi [Populus fastigiata Desf.] [Populus dilatata Ait.]
HABIT.—A tree 75-100 feet high, with a short, ridged and buttressed trunk 4-6 feet in diameter and a narrow, spire-like crown of erect branches.
LEAVES.—Alternate, simple, 2-4 inches long, and usually somewhat broader than long; broad-deltoid, abruptly acuminate; finely but bluntly crenate-serrate; thick and firm; dark green and shining above, lighter and more or less lustrous beneath; petioles slender, laterally compressed, 1-2 inches long.
FLOWERS.—April-May, before the leaves; dioecious; the staminate in sessile, dark red, cylindrical catkins about 3 inches long; the pistillate not present in the United States; calyx 0; corolla 0; stamens about 8, with white filaments and purple anthers.
FRUIT.—Not formed in the United States in the absence of pistillate flowers.
WINTER-BUDS.—Terminal bud conical, slightly angled, taper-pointed, glutinous, about 3/8 inch long; lateral buds smaller, appressed.
BARK.—Twigs glabrous, shining yellow, becoming gray; thick and gray-brown on old trunks, deeply and irregularly furrowed.
WOOD.—Light, soft, easily worked, not liable to splinter, weak, not durable, light red-brown, with thick, nearly white sapwood.
NOTES.—Thought to be a native of Afghanistan. Very rapid in growth. Short-lived. Spreads by means of suckers and fallen branches. Useful for ornamental purposes. Because of crowding the limbs die early, which remain and cause the tree to look unsightly.
JUGLANDACEAE
SUMMER KEY TO THE SPECIES OF JUGLANS
| a. | Leaflets 11-17, the terminal usually present; pith of twigs chocolate-brown; bark of trunk rather smooth, or fissured, with broad, flat, whitish ridges; fruit elongated, sticky-downy. | J. cinerea, p. [63]. |
| aa. | Leaflets 13-23, the terminal often lacking; pith of twigs cream colored; bark of trunk rough, brownish or blackish, deeply furrowed by broad, rounded ridges; fruit globose, not sticky-downy. | J. nigra, p. [65]. |
WINTER KEY TO THE SPECIES OF JUGLANS
| a. | Pith chocolate-brown; leaf-scar with downy pad above; fruit elongated, sticky-downy; terminal bud 1/2-3/4 inch long; bark rather smooth, or fissured, with broad, flat, whitish ridges. | J. cinerea, p. [63]. |
| aa. | Pith cream colored; leaf-scar without downy pad above; fruit globose, not sticky-downy; terminal bud 1/3 inch long; bark rough, brownish or blackish, deeply furrowed by broad, rounded ridges. | J. nigra, p. [65]. |
Butternut
1. Winter twig, × 1.
2. Leaf, × 1/6
3. Leaflet, × 1/2
4. Flowering branchlet, × 1/2.
5. Staminate flower, enlarged.
6. Pistillate flower, enlarged.
7. Fruit, × 1/2.
JUGLANDACEAE
Butternut
Juglans cinerea L.
HABIT.—A medium-sized tree 40-60 feet high, with a short trunk 2-3 feet in diameter; forming a wide-spreading crown of large, horizontal branches and stout, stiff branchlets.
LEAVES.—Alternate, compound, 15-30 inches long. Leaflets 11-17, 2-4 inches long and one-half as broad; sessile, except the terminal; oblong-lanceolate; finely serrate; thin; yellow-green and rugose above, pale and soft-pubescent beneath. Petioles stout, hairy.
FLOWERS.—May, with the leaves; monoecious; the staminate in cylindrical, greenish, drooping catkins 3-5 inches long; calyx 6-lobed, borne on a hairy bract; corolla 0; stamens 8-12, with brown anthers; the pistillate solitary or several on a common peduncle, about 1/3 inch long, their bracts and bractlets sticky-hairy; calyx 4-lobed, hairy; corolla 0; styles 2; stigmas 2, fringed, spreading, bright red.
FRUIT.—October; about 2-1/2 inches long, cylindrical, pointed, greenish, sticky-downy, solitary or borne in drooping clusters of 3-5; nuts with rough shells, inclosing a sweet, but oily kernel; edible.
WINTER-BUDS.—Terminal bud 1/2-3/4 inch long, oblong-conical, obliquely blunt, somewhat flattened, brownish, pubescent.
BARK.—Twigs orange-brown or bright green, rusty-pubescent, becoming smooth and light gray; gray and smoothish on young trunks, becoming brown on old trunks, narrow-ridged, with wide furrows.
WOOD.—Light, soft, weak, coarse-grained, light brown, with thin, lighter colored sapwood.
DISTRIBUTION.—Of common occurrence in the southern half of the Lower Peninsula.
HABITAT.—Prefers low, rich woods; river-banks; low hillsides.
NOTES.—Leaves appear late and fall early. Pith chambered, chocolate-brown. Large trees usually unsound. Not easily transplanted.
Black Walnut
1. Winter twig, × 1.
2. Leaf, × 1/6.
3. Leaflet, × 1/2.
4. Flowering branchlet, × 1/2.
5. Staminate flower, back view, enlarged.
6. Pistillate flower, enlarged.
7. Fruit, × 1/2.
JUGLANDACEAE
Black Walnut
Juglans nigra L.
HABIT.—A large tree 60-80 feet high, with a massive trunk 2-5 feet in diameter; forming an open, capacious crown of heavy branches and coarse branchlets.
LEAVES.—Alternate, compound, 1-2 feet long. Leaflets 13-23, the terminal often lacking, 2-4 inches long and one-half as broad; sessile; ovate-lanceolate, taper-pointed; sharp-serrate; thin; yellow-green and glabrous above, lighter and soft-pubescent beneath. Petioles stout, pubescent. Foliage aromatic when bruised.
FLOWERS.—May, with the leaves; monoecious; the staminate in cylindrical, greenish, drooping catkins 3-5 inches long; calyx 6-lobed, borne on a hairy bract; corolla 0; stamens numerous, with purple anthers; the pistillate solitary or several on a common peduncle, about 1/4 inch long, their bracts and bractlets hairy; calyx 4-lobed, pubescent; corolla 0; styles and stigmas 2.
FRUIT.—October; globose, 1-1/2-2 inches in diameter, smooth, not viscid; solitary or borne in clusters of 2-3; nuts with irregularly furrowed shell, inclosing a sweet, edible kernel.
WINTER-BUDS.—Terminal bud 1/3 inch long, ovoid, obliquely blunt, slightly flattened, silky-tomentose.
BARK.—Twigs brownish and hairy, becoming darker and smooth; thick, brownish or blackish on the trunk and deeply furrowed by broad, rounded ridges.
WOOD.—Heavy, hard, strong, close-grained, very durable in contact with the soil, rich dark brown, with thin, lighter colored sapwood.
DISTRIBUTION.—Lower Peninsula as far north as Bay City, but more abundant in the southern portion of its range.
HABITAT.—Prefers rich bottom-lands and fertile hillsides.
NOTES.—Leaves appear late and fall early. Fruit very aromatic. Pith chambered, cream colored. The juices from the husk stain the hands brown. Not easily transplanted. Often infested with caterpillars.
SUMMER KEY TO THE SPECIES OF CARYA
| a. | Bark of trunk essentially smooth, not deeply furrowed norshaggy; husk of fruit less than 1/8 inch thick. | |||
| b. | Leaflets usually 5-7, glabrous beneath; buds dome-shaped,greenish; kernel of nut sweet. | |||
| c. | Twigs long-hairy; fruit less than 1 inch long. | C. microcarpa, p. [75]. | ||
| cc. | Twigs glabrous or nearly so; fruit 1-1/2-2 inches long. | C. glabra, p. [77]. | ||
| bb. | Leaflets usually 7-11, more or less downy beneath; budselongated, bright yellow; kernel of nut bitter. | C. cordiformis, p. [79]. | ||
| aa. | Bark of trunk deeply furrowed or shaggy; husk of fruitmore than 1/8 inch thick. | |||
| b. | Twigs more or less pubescent; leaflets 5-7, more or lesspubescent beneath. | |||
| c. | Twigs brownish; buds densely hairy; fruit 1-1/2-2 incheslong. | C. alba, p. [73]. | ||
| cc. | Twigs orange; buds merely puberulous; fruit 1-3/4-2-1/2inches long; (leaflets usually 7). | C. laciniosa, p. [71]. | ||
| bb. | Twigs tending to be glabrous; leaflets usually 5, glabrousbeneath. | C. ovata, p. [69]. | ||
WINTER KEY TO THE SPECIES OF CARYA
| a. | Bark of trunk essentially smooth, not deeply furrowed norshaggy; husk of fruit less than 1/8 inch thick. | |||
| b. | Terminal bud narrow, long-pointed, flattish, bright yellow;kernel of nut bitter. | C. cordiformis, p. [79]. | ||
| bb. | Terminal bud broad, dome-shaped, not bright yellow;kernel of nut sweet. | |||
| c. | Buds greenish; twigs glabrous; fruit 1-1/2-2 inches long. | C. glabra, p. [77]. | ||
| cc. | Buds red-brown; twigs long-hairy; fruit less than 1 inchlong. | C. microcarpa, p. [75]. | ||
| aa. | Bark of trunk deeply furrowed or shaggy; husk of fruitmore than 1/8 inch thick. | |||
| b. | Twigs more or less pubescent; buds more or less pubescent. | |||
| c. | Buds 1/2-3/4 inch long, densely hairy; outer bud-scalesdeciduous in autumn; twigs brownish; fruit 1-1/2-2 incheslong. | C. alba, p. [73]. | ||
| cc. | Buds about 1 inch long, merely puberulous; outer bud-scalespersistent until spring; twigs orange colored;fruit 1-3/4-2-1/2 inches long. | C. laciniosa, p. [71]. | ||
| bb. | Twigs tending to be glabrous; buds glabrous or nearly so. | C. ovata, p. [69]. | ||
Shagbark Hickory. Shellbark Hickory
1. Winter twig, × 1.
2. Portion of twig, enlarged.
3. Leaf, × 1/3.
4. Flowering branchlet, × 1/2.
5. Staminate flower, enlarged.
6. Pistillate flower, enlarged.
7. Fruit, × 1/2.