1. POPULUS L. Poplar.
Large fast-growing trees, with pale furrowed bark, terete or angled branchlets, resinous winter-buds covered by several thin scales, those of the first pair small and opposite, the others imbricated, increasing in size from below upward, accrescent and marking the base of the branchlet with persistent ring-like scars, and thick roots. Leaves involute in the bud, usually ovate or ovate-lanceolate, entire, dentate with usually glandular teeth, or lobed, penniveined, turning yellow in the autumn; petioles long, often laterally compressed, sometimes furnished at the apex on the upper side with 2 nectariferous glands, leaving in falling oblong often obcordate, elliptic, arcuate, or shield-shaped leaf-scars displaying the ends of 3 nearly equidistant fibro-vascular bundles; stipules caducous, those of the first leaves resembling the bud-scales, smaller higher on the branch, and linear-lanceolate and scarious on the last leaves. Flowers in pendulous stalked aments, the pistillate lengthening and rarely becoming erect before maturity; scales obovate, gradually narrowed into slender stipes, dilated and lobed, palmately cleft or fimbriate at apex, membranaceous, glabrous or villose, more crowded on the staminate than on the pistillate ament, usually caducous; disk of the flower broadly cup-shaped, often oblique, entire, dentate or irregularly lobed, fleshy or membranaceous, stipitate, usually persistent under the fruit; stamens 4—12 or 12—60 or more, inserted on the disk, their filaments free, short, light yellow; anthers ovoid or oblong, purple or red; ovary sessile in the bottom of the disk, oblong-conical subglobose or ovoid-oblong, cylindric or slightly lobed, with 2 or 3 or rarely 4 placentas; styles usually short; stigmas as many as the placentas, divided into filiform lobes or broad, dilated, 2-parted or lobed. Fruit ripening before the full growth of the leaves, greenish, reddish brown, or buff color, oblong-conic, subglobose or ovoid-oblong, separating at maturity into 2—4 recurved valves. Seeds broadly obovoid or ovoid, rounded or acute at the apex, light chestnut-brown; cotyledons elliptic.
Populus in the extreme north often forms great forests, and is common on the alluvial bottom-lands of streams and on high mountain slopes, ranging from the Arctic Circle to northern Mexico and Lower California and from the Atlantic to the Pacific in the New World, and to northern Africa, the southern slopes of the Himalayas, central China, and Japan in the Old World. Of the thirty-four species now generally recognized fifteen are found in North America. The wood of many of the American species is employed in large quantities for paper-making, and several species furnish wood used in construction and in the manufacture of small articles of wooden ware. The bark contains tannic acid and is used in tanning leather and occasionally as a tonic, and the fragrant balsam contained in the buds of some species is occasionally used in medicine. The rapidity of their growth, their hardiness and the ease with which they can be propagated by cuttings, make many of the species useful as ornamental trees or in wind-breaks, although planted trees often suffer severely from the attacks of insects boring into the trunks and branches. Of the exotic species, the Abele, or White Poplar, Populus alba L., of Europe and western Asia, and its fastigiate form, and the so-called Lombardy Poplar, a tree of pyramidal habit and a form of the European and Asiatic Populus nigra L., and one of its hybrids, have been largely planted in the United States.
Populus, of obscure derivation, is the classical name of the Poplar.
CONSPECTUS OF THE NORTH AMERICAN SPECIES.
Stigmas 2, 2-lobed, their lobes filiform; leaf stalks elongated, laterally compressed; buds slightly resinous. Leaves finely serrate; winter-buds glabrous.1. [P. tremuloides] (A, B, F, G). Leaves coarsely serrate; winter-buds tomentose or pubescent.2. [P. grandidentata.] Stigmas 2—4, 2-lobed and dilated, their lobes variously divided; buds resinous. Leaf-stalks round. Leaves tomentose below early in the season, broadly ovate, acute or rounded at apex.3. [P. heterophylla] (A, C). Leaves glabrous or pilose below. Leaves dark green above, pale, rarely pilose below. Ovary and capsule glabrous.4. [P. tacamahacca] (A, B, F). Ovary and capsule tomentose or pubescent.5. [P. trichocarpa] (B, F). Leaves light green on both surfaces, glabrous. Leaves lanceolate to ovate-lanceolate.6. [P. angustifolia] (F). Leaves rhombic-lanceolate to ovate.7. [P. acuminata] (F). Leaf-stalks laterally compressed. Leaves without glands at apex of the petiole, coarsely serrate, thick. Pedicels shorter than the fruit. Disk cup-shaped. Branchlets stout; capsule ⅓′—½′ long.8. [P. Fremontii] (G, H). Branchlets slender; capsule not more than ¼′ long.9. [P. arizonica] (F, H). Disk minute. Branchlets glabrous; leaves broad-ovate to deltoid, long-pointed and acuminate at apex.10. [P. texana] (C). Branchlets pubescent; leaves broad-ovate, abruptly short-pointed or acute at apex.11. [P. McDougallii] (G, H). Pedicels 2 or 3 times longer than the fruit; leaves broadly deltoid, abruptly short-pointed.12. [P. Wislizenii] (E, F). Leaves furnished with glands at apex of the petiole. Branchlets stout; leaves thick. Winter-buds puberulous; leaves coarsely serrate; branchlets light yellow.13. [P. Sargentii] (F). Winter-buds glabrous; leaves less coarsely serrate; branchlets gray or reddish brown.14. [P. balsamifera] (A, C). Branchlets slender; leaves thin, ovate, cuneate or rounded at base, finely serrate.15. [P. Palmeri] (E).
1. [Populus tremuloides] Michx. Aspen. Quaking Asp.
Leaves ovate to broad-ovate or rarely reniform (var. reniformis Tidestrom) abruptly short-pointed or acuminate at apex rounded or rarely cuneate at the wide base, closely crenately serrate with glandular teeth, thin, green and lustrous above, dull green or rarely pale below, up to 4½′ long and broad with a prominent midrib, slender primary veins and conspicuous reticulate veinlets; petioles slender, compressed laterally, 1½′—3′ long. Flowers: aments 1½′—2½′ long, the pistillate becoming 4′ in length at maturity; scales deeply divided into 3—5 linear acute lobes fringed with long soft gray hairs; disk oblique, the staminate entire, the pistillate slightly crenate; stamens 6—12; ovary conic, with a short thick style and erect stigmas thickened and club-shaped below and divided into linear diverging lobes. Fruit maturing in May and June, oblong-conic, light green, thin-walled, nearly ¼′ long; seeds obovoid, light brown, about 1/32′ in length.
A tree, 20°—40° high, with a trunk 18′—20′ in diameter, slender remote and often contorted branches somewhat pendulous toward the ends, forming a narrow symmetrical round-topped head, and slender branchlets covered with scattered oblong orange-colored lenticels, bright red-brown and very lustrous during their first season, gradually turning light gray tinged with red, ultimately dark gray, and much roughened for two or three years by the elevated leaf-scars. Winter-buds slightly resinous, conic, acute, often incurved, about ¼′ long, narrower than the more obtuse flower-buds, with 6 or 7 lustrous glabrous red-brown scales scarious on the margins. Bark thin, pale yellow-brown or orange-green, often roughened by horizontal bands of circular wart-like excrescences, frequently marked below the branches by large rows of lunate dark scars. Wood light brown, with nearly white sapwood of 25—30 layers of annual growth.
Distribution. Southern Labrador to the southern shores of Hudson’s Bay and northwesterly to the mouth of the Mackenzie River, through the northern states to the mountains of Pennsylvania, northern Ohio, Indiana and Illinois, eastern and central Iowa and northeastern Missouri; common and generally distributed usually on moist sandy soil and gravelly hillsides; most valuable in the power of its seeds to germinate quickly in soil made infertile by fire and of its seedlings to grow rapidly in exposed situations; westward passing into the var. aurea Daniels, with thicker rhombic to semiorbicular or broad-ovate generally smaller leaves, usually pale on the lower surface, rounded or acute and minutely short-pointed at apex, rounded or cuneate at base, often entire with slightly thickened margins, or occasionally coarsely crenately serrate, with inconspicuous reticulate veinlets, turning bright golden yellow in the autumn before falling.
A tree occasionally 100° high with a trunk up to 3° in diameter, with pale often white bark, becoming near the base of old stems 2′ thick, nearly black, and deeply divided into broad flat ridges broken on the surface into small appressed plate-like scales.
Distribution. Valley of the Yukon River to Saskatchewan, and southward through the mountain ranges of the Rocky Mountain region to southern New Mexico, the San Francisco Mountains of Arizona, and westward to the valley of the Skeena River, British Columbia, western Washington and Oregon, the western slopes of the Sierra Nevada and the high mountains of southern California, and eastward to North and South Dakota and western Nebraska; on the mountains of Chihuahua, and on the Sierra de Laguna, Lower California.
Populus tremuloides var. vancouveriana Sarg.
Populus vancouveriana Trel.
Leaves broadly ovate to semiorbicular, abruptly short-pointed or rounded at apex, rounded or slightly cordate at the broad base, coarsely crenately serrate and sometimes obscurely crispate on the margins, when they unfold covered below and on the petioles with a thick coat of long matted pale hairs, and slightly villose, glabrous or nearly glabrous above, soon glabrous, and at maturity thick dark green, lustrous and scabrate on the upper surface, paler on the lower surface, 3′—4½′ long and broad, with a prominent midrib and primary veins; petioles slender, compressed, becoming glabrous, 2′—3′ in length. Flowers: staminate aments slightly villose; pedicels pubescent; disk of the flower puberulous toward the base; flowers as in the species; pistillate aments 2′—2¼′ long, becoming 3′—3½′ in length at maturity; the rachis, pedicels and slightly lobed disk of the flower densely villose-pubescent; ovary conic, pubescent, with a short style and stigma divided into narrow divergent lobes. Fruit on pedicel not more than 1/24′ in length, oblong-conic, pubescent or glabrous, ¼′ long.
A tree 30°—36° high, with a trunk 12′—16′ in diameter, stout spreading branches forming a round-topped head, stout, reddish brown pubescent or puberulous branchlets often becoming glabrous during their first summer. Winter-buds acute, tomentose, pubescent or glabrous.
Coast of Vancouver Island, British Columbia and shores of Puget Sound; Tualitin, Washington County, and valley of the Willamette River at Corvallis, Benton County, Oregon.
2. [Populus grandidentata] Michex. Poplar.
Leaves semiorbicular to broad-ovate, short-pointed at apex, rounded, abruptly cuneate or rarely truncate at the broad entire base, coarsely repand-dentate above with few stout incurved teeth, covered like the petioles early in the season with white tomentum, soon glabrous, thin and firm in texture, dark green above, paler on the lower surface, 2′—3′ long, 2′—2½′ wide, with a prominent yellow midrib, conspicuously forked veins, and reticulate veinlets; petioles slender, laterally compressed, 1½′—2½′ long. Flowers: aments pubescent, 1½′—2½′ long, the pistillate becoming 4′—5′ long at maturity; scales pale and scarious below, divided above into 5 or 6 small irregular acute lobes covered with soft pale hairs; disk shallow, oblique, the staminate entire, the pistillate slightly crenate; stamens 6—12, with short slender filaments and light red anthers; ovary oblong-conic, bright green, puberulous, with a short style, and spreading stigmas divided nearly to the base into elongated filiform lobes. Fruit ripening before the leaves are fully grown, often more or less curved above the middle, light green and puberulous, thin-walled, 2-valved, about ⅛′ long; pedicel slender, pubescent, about 1/12′ in length; seeds minute dark brown.
A tree, often 60°—70° high, with a trunk occasionally 2° in diameter, slender rather rigid branches forming a narrow round-topped head, and stout branchlets marked by scattered oblong orange-colored lenticels, coated when they first appear with thick hoary deciduous tomentum, becoming during their first year dark red-brown or dark orange-colored, glabrous, lustrous, or covered with a delicate gray pubescence, and in their second year dark gray sometimes slightly tinged with green and much roughened by the elevated 3-lobed leaf-scars; generally smaller, and usually not more than 30°—40° tall. Winter-buds terete, broadly ovoid, acute, with light bright chestnut-brown scales, pubescent during the winter especially on their thin scarious margins, about ⅛′ long and not more than half the size of the flower-buds. Bark thin, smooth, light gray tinged with green, becoming near the base of old trunks ¾′—1′ thick, dark brown tinged with red, irregularly fissured and divided into broad flat ridges roughened on the surface by small thick closely appressed scales. Wood light brown, with thin nearly white sapwood of 20—30 layers of annual growth.
Distribution. Rich moist sandy soil near the borders of swamps and streams; Nova Scotia, through New Brunswick, southern Quebec and Ontario to northern Minnesota, southward through the northern states to Pennsylvania, northern Ohio, and eastern (Muscatine County) and central Iowa, and westward to central Kentucky and Tennessee; passing into the var. meridionalis Tidestrom with broad-ovate acuminate leaves with more numerous teeth, often 4′—5′ long and 3′ wide; the common form in Maryland, northern Delaware, the piedmont region of Virginia and North Carolina, southern Ohio, and southern Indiana and Illinois; rare northward to northern New England.
3. [Populus heterophylla] L. Swamp Cottonwood. Black Cottonwood.
Leaves broadly ovate, gradually narrowed and acute, short-pointed or rounded at apex, slightly cordate or truncate or rounded at the wide base, usually furnished with a narrow deep sinus, finely or coarsely crenately serrate with incurved glandular teeth, covered as they unfold with thick hoary deciduous tomentum, becoming thin and firm in texture, dark deep green above, pale and glabrous below, with a stout yellow midrib, forked veins and conspicuous reticulate veinlets, 4′—7′ long, 3′—6′ wide; petioles slender terete tomentose or nearly glabrous 2½′—3½′ in length. Flowers: staminate aments broad, densely flowered, 1′ long, erect when the flowers first open, becoming pendulous and 2′—2½′ long; scales narrowly oblong-obovate, brown, scarious and glabrous below, divided into numerous elongated filiform light red-brown lobes; disk oblique, slightly concave; stamens 12—20, with slender filaments about as long as the large dark red anthers; pistillate aments slender, pendulous, few-flowered, 1′—2′ long, becoming erect and 4′—6′ long before maturing, their scales concave and infolding the flowers, linear-obovate, brown and scarious, laterally lobed, fimbriate above the middle, caducous; disk thin, irregularly divided in numerous triangular acute teeth, long-stalked; ovary ovoid, terete or obtusely 3-angled, with a short stout elongated style and 2 or 3 much-thickened dilated 2 or 3-lobed stigmas. Fruit on elongated pedicels, ripening when the leaves are about one third grown, ovoid, acute, dark red-brown, rather thick-walled, 2 or 3-valved, about ½′ long; seeds obovoid, minute, dark red-brown.
A tree, 80°—90° high, with a tall trunk 2°—3° in diameter, short rather slender branches forming a comparatively narrow round-topped head, and stout branchlets, marked by small elongated pale lenticels, coated at first with hoary caducous tomentum, becoming dark brown and rather lustrous or ashy gray, or rarely pale orange color and glabrous or slightly puberulous, or covered with a glaucous bloom in their first winter, growing darker in their second year and much roughened by the large thickened leaf-scars; usually much smaller and at the north rarely more than 40° tall. Winter-buds slightly resinous, broadly ovoid, acute, with bright red-brown scales, about ¼′ long and about one half the size of the flower-buds. Bark on young trunks divided by shallow fissures into broad flat ridges separating on the surface into thick plate-like scales, becoming on old trunks ¾′—1′ thick, light brown tinged with red, and broken into long narrow plates attached only at the middle and sometimes persistent for many years. Wood dull brown, with thin lighter brown sapwood of 12—15 layers of annual growth; now often manufactured into lumber in the valley of the Mississippi River and in the Gulf states, and as black poplar used in the interior finish of buildings.
Distribution. Southington, Connecticut, and Northport, Long Island, southward near the coast to southern Georgia, and the valley of the lower Apalachicola River, Florida, through the Gulf states to western Louisiana, and through Arkansas to southeastern Missouri, western Kentucky and Tennessee, southern Illinois and Indiana, and in central and northern Ohio (Williams, Ottawa and Lake Counties); in the north Atlantic states in low wet swamps, rare and local; more common south and west on the borders of river swamps; very abundant and of its largest size in the valley of the lower Ohio and in southeastern Missouri, eastern Arkansas, and western Mississippi.
4. [Populus tacamahacca] Mill. Balsam. Tacamahac.
Populus balsamifera Du Roi, not L.
Leaves ovate-lanceolate, gradually narrowed and acuminate at apex, cordate or rounded at base, or narrow-elliptic and acute or acuminate at the ends, finely crenately serrate, with slightly thickened revolute margins, coated when they unfold with the gummy secretions of the bud, glabrous, or puberulous on the under side of the midrib, becoming thin and firm in texture, deep dark green and lustrous above, pale green or glaucous and more or less rusty and conspicuously reticulate-venulose below, 3′—5′ long, 1½′—3′ wide, with thin veins running obliquely almost to the margins; petioles slender, terete, 1½′ long, glabrous or rarely puberulous. Flowers: aments long-stalked, the pistillate becoming 4′—5′ long before the fruit ripens, glabrous or pubescent; scales broadly obovate, light brown and scarious, often irregularly 3-parted at apex, cut into short thread-like brown lobes; disk of the staminate flower oblique, short-stalked; stamens 20—30, with short filaments and large light red anthers; disk of the pistillate flower cup-shaped; ovary ovoid, slightly 2-lobed, with two nearly sessile large oblique dilated crenulate stigmas. Fruit ovoid-oblong, acute and often curved at apex, 2-valved, light brown, about ¼′—⅓′ long, nearly sessile or short-stalked, ½′—⅛′ in length; seeds oblong-obovoid, pointed at apex, narrowed and truncate at base, light brown, about 1/12′ long.
A tree, often 100° high, with a tall trunk 6°—7° in diameter, stout erect branches usually more or less contorted near the end, forming a comparatively narrow open head, and glabrous or occasionally pubescent branchlets marked by oblong bright orange-colored lenticels, much roughened by the thickened leaf-scars, at first red-brown and glabrous or pubescent, becoming bright and lustrous in their first winter, dark orange-colored in their second year, and finally gray tinged with yellow-green; usually much smaller toward the southern limits of its range. Winter-buds saturated with a yellow balsamic sticky exudation, ovoid, terete, long-pointed; terminal 1′ long, ⅓′ broad; axillary about ¾′ long, 1/16′ broad, with 5 oblong pointed concave closely imbricated thick chestnut-brown lustrous scales. Bark light brown tinged with red, smooth or roughened by dark excrescences, becoming on old trunks ¾′—1′ thick, gray tinged with red, and divided into broad rounded ridges covered by small closely appressed scales. Wood light brown, with thick nearly white sapwood.
Distribution. Low often inundated river-bottom lands and swamp borders; Labrador to latitude 65° north in the valley of the Mackenzie River, and to the Alaskan coast, south to northern New England and New York, central Michigan, Minnesota (except in southern and southwestern counties), Turtle Mountains, Rolette County, North Dakota, the Black Hills of South Dakota, northwestern Nebraska (basin of Hat Creek), and in Colorado; the characteristic tree on the streams of the prairie region of British America, attaining its greatest size on the islands and banks of the Peace, Athabasca, and other tributaries of the Mackenzie; common in all the region near the northern boundary of the United States from Maine to the western limits of the Atlantic forests; the largest of the sub-Arctic American trees, and in the far north the most conspicuous feature of vegetation; passing into the variety Michauxii Farwell, with more cordate leaves, slightly pilose on the under side of the midrib and veins; common from Aroostook County, Maine, to the Province of Quebec, Newfoundland, and the shores of Hudson Bay.
Often planted at the north for shelter or ornament.
Populus candicans Ait., the Balm of Gilead of which only the pistillate tree is known, has often been considered a variety of the North American Balsam Poplar. This tree has been long cultivated in the northeastern part of the country and has sometimes escaped from cultivation and formed groves of considerable extent, as on the banks of Cullasagee Creek on the western slope of the Blue Ridge in Macon County, North Carolina. The fact that only one sex is known suggests hybrid origin but of obscure and possibly partly of foreign origin.
5. [Populus trichocarpa] Hook. Black Cottonwood. Balsam Cottonwood.
Leaves broad-ovate, acute or acuminate at apex, rounded or abruptly cuneate at base, finely crenately serrate, glabrous, dark green above, pale and rusty or silvery white and conspicuously reticulate-venulose below, 3′—4′ long, 2′—2½′ wide; petioles slender, pubescent, puberulous, pilose or rarely glabrous, 1½′—2′ in length. Flowers: aments stalked, villose-pubescent, the staminate densely flowered, 1½′—2′ long, ⅓′ thick, the pistillate loosely flowered, 2½′—3′ long, becoming 4′—5′ long before the fruit ripens; scales dilated at the apex, irregularly cut into numerous filiform lobes, glabrous or slightly puberulous on the outer surface; disk of the staminate flower broad, slightly oblique; stamens 40—60, with slender elongated filaments longer than the large light purple anthers; disk of the pistillate flower deep cup-shaped, with irregularly crenate or nearly entire revolute margins; ovary subglobose, coated with thick hoary tomentum, with 3 nearly sessile broadly dilated deeply lobed stigmas. Fruit subglobose, nearly sessile, pubescent, thick-walled, 3-valved; seeds obovoid, apiculate at the gradually narrowed apex, light brown, puberulous toward the ends, 1/12′ long.
A tree, 30°—100° high, with a trunk 1°—3° in diameter, erect branches forming an open head, and slender branchlets terete or slightly angled while young, marked by many orange-colored lenticels, glabrous or when they first appear coated with deciduous rufous or pale pubescence, reddish brown during their first year, gradually becoming dark gray, and roughened by the greatly enlarged and thickened elevated leaf-scars. Winter-buds resinous, fragrant, ovoid, long-pointed, frequently curved above the middle, ¾′ long and ¼′ thick, with 6 or 7 light orange-brown slightly puberulous scales scarious on the margins. Bark ½′—2½′ thick, ashy gray, deeply divided into broad rounded ridges broken on the surface into thick closely appressed scales. Wood light, dull brown, with thin nearly white sapwood.
Distribution. In California in small groves with widely scattered individuals on the coast ranges, the western slope of the Sierra Nevada up to elevations of 6000°—8000°, and on the southern mountains to Mt. Palomar in San Diego County; on the California islands, and on the western slopes of the San Pedro Mártir Mountains, Lower California.
On the high Sierra Nevada and in northern California passing into the var. hastata A. Henry, differing in its thicker leaves, usually longer in proportion to their width, often long-acuminate, rounded or cordate at base, frequently 5′ or 6′ long and 3′ or 4′ wide, with glabrous petioles and larger sometimes nearly glabrous capsules on glabrous or pubescent aments, sometimes 10′—12′ in length, and in its glabrous young branchlets.
A tree sometimes 200° high, with a trunk 7°—8° in diameter, and the largest deciduous-leaved tree of northwestern North America. The wood is largely used in Oregon and Washington for the staves of sugar barrels and in the manufacture of wooden ware.
Distribution. In open groves on rich bottom lands of streams from Siskiyou County, California, to southern Alaska; eastward in the United States through Oregon and Washington to western and southern Idaho; and to the mountains of western Nevada; in British Columbia to the valley of the Columbia River; on the banks of the east fork of the Kaweah River, Tulare County, California, at 10,000° above the sea.
6. [Populus angustifolia] James. Narrow-leaved Cottonwood.
Populus fortissima A. Nels & Macbr.
Leaves lanceolate, ovate-lanceolate, elliptic or rarely obovate, narrowed to the tapering acute or rounded apex, gradually narrowed and cuneate or rounded at base, finely or on vigorous shoots coarsely serrate, thin and firm, bright yellow-green above, glabrous or rarely puberulous and paler below, 2′—3′ long, ½′—1′ wide, or on vigorous shoots occasionally 6′—7′ long, and 1½′ wide, with a stout yellow midrib and numerous slender-oblique primary veins arcuate and often united near the slightly thickened revolute margins; petioles slender, somewhat flattened on the upper side, and in falling leaving small nearly oval obcordate scars. Flowers: aments densely flowered, glabrous, short-stalked, ½′—2½′ long, the pistillate becoming 2½′—4′ long before the fruit ripens; scales broadly obovate, glabrous, thin, scarious, light brown, deeply and irregularly cut into numerous dark red-brown filiform lobes; disk of the staminate flower cup-shaped, slightly oblique, short-stalked; stamens 12—20, with short filaments and large light red anthers; disk of the pistillate flower shallow, cup-shaped, slightly and irregularly lobed, short-stalked; ovary ovoid, more or less 2-lobed, with a short or elongated style and 2 oblique dilated irregularly lobed stigmas. Fruit broadly ovoid, often rather abruptly contracted above the middle, short-pointed, thin-walled, 2-valved; pedicels often ⅓′ long; seeds ovoid or obovoid, rather obtuse, light brown, nearly ⅛′ long.
A tree, 50°—60° high, with a trunk rarely more than 18′ in diameter, slender erect branches forming a narrow and usually pyramidal head, and slender glabrous or rarely puberulous branchlets marked by pale lenticels, at first light yellow-green, becoming bright or dark orange color in their first season, pale yellow in their second winter, and ultimately ashy gray. Winter-buds very resinous, ovoid, long-pointed, covered by usually 5 thin concave chestnut-brown scales; terminal ¼′—½′ long and nearly twice as large as the axillary buds. Bark ¾′—1′ thick, light yellow-green, divided near the base of old trees by shallow fissures into broad flat ridges, smooth and much thinner above. Wood light brown, with thin nearly white sapwood of 10—30 layers of annual growth.
Distribution. Banks of streams usually at altitudes of 5000°—10,000° above the sea; southern Alberta to the Black Hills of South Dakota and northwestern Nebraska (basin of Hat Creek) westward through Wyoming, Montana and Idaho to Yakima County, Washington, and southward to central Nevada, southwestern New Mexico (Silver City, Grant County) and northern Arizona; the common Cottonwood of northern Colorado, Utah, Wyoming, southern Montana, and eastern Idaho; on the mountains of Chihuahua.
7. [Populus acuminata] Rydb. Cottonwood.
Leaves rhombic-lanceolate to ovate, abruptly acuminate, gradually or abruptly narrowed and cuneate or concave-cuneate, or rarely broad and rounded at the mostly entire base, coarsely crenately serrate except near the apex, dark green and lustrous above, dull green below, 2′—4′ long, ¾′—2′ wide, with a slender yellow midrib, thin remote primary veins and obscure reticulate veinlets; petioles slender, nearly terete, 1′—3′ long. Flowers: aments slender, short-stalked, 2′—3′ long, the pistillate becoming 4′ or 5′ long before the fruit ripens; scales scarious, light brown, glabrous, dilated and irregularly divided into filiform lobes; disk of the staminate flower wide, oblique, and membranaceous; stamens numerous, with short filaments and dark red anthers; disk of the pistillate flower deep cup-shaped; ovary broad-ovoid, gradually narrowed above, with large laciniately lobed nearly sessile stigmas. Fruit pedicellate, oblong-ovoid, acute, thin-walled, slightly pitted, about ⅓′ long, 3 or rarely 2-valved; seeds oblong-obovoid, rounded at the apex, light brown, about 1/12′ in length.
A tree, usually about 40° high, with a trunk 12′—18′ in diameter, stout spreading and ascending branches forming a compact round-topped head, and slender terete or slightly 4-angled pale yellow-brown branchlets roughened for two or three years by the elevated oval horizontal leaf-scars. Winter-buds acuminate, resinous, about ⅓′ long, with 6 or 7 light chestnut-brown lustrous scales. Bark on young stems and large branches smooth, nearly white, becoming on old trunks pale gray-brown, about ½′ thick, deeply divided into broad flat ridges.
Distribution. Banks of streams in the arid eastern foothill region of the Rocky Mountains; Assiniboia to the Black Hills of South Dakota, northwestern Nebraska, eastern Wyoming, southern Colorado, and southwestern New Mexico (Fort Bayard, Grant County); in Colorado crossing the Continental Divide to southeastern Utah; passing into the var. Rehderi Sarg. differing in the larger leaves on longer petioles, and in the pubescent branchlets and winter-buds. Borders of streams southeastern New Mexico.
Sometimes planted as a shade-tree in the streets of cities in the Rocky Mountain region.
× Populus Andrewsii Sarg. intermediate in its character between P. acuminata and P. Sargentii and believed to be a natural hybrid of these species has been found growing naturally near Boulder and Walsenburg, Colorado, and as a street tree in Montrose, Colorado.
8. [Populus Fremontii] S. Wats. Cottonwood.
Leaves deltoid or reniform, generally contracted into broad short entire points, or rarely rounded or emarginate at apex, truncate, slightly cordate or abruptly cuneate at the entire base, coarsely and irregularly serrate, with few or many incurved gland-tipped teeth, coated like the petioles when they unfold with short spreading caducous pubescence, at maturity thick and firm, glabrous bright green and lustrous, 2′—2½′ long, 2½′—3′ wide, with a thin yellow midrib and 4 or 5 pairs of slender veins; petioles flattened, yellow, 1½′—3′ long. Flowers: staminate aments densely flowered, 1½′—2′ long, nearly ½′ thick, with slender glabrous stems, the pistillate sparsely flowered, with stout glabrous or puberulous stems, becoming before the fruit ripens 4′ or 5′ long; scales light brown, thin and scarious, dilated and irregularly cut at apex into filiform lobes; disk of the staminate flower broad, oblique, slightly thickened on the entire revolute margin; stamens 60 or more, with large dark red anthers; disk of the pistillate flower cup-shaped; ovary ovoid or ovoid-oblong, with 3 or rarely 4 broad irregularly crenately lobed stigmas. Fruit ovoid, acute or obtuse, slightly pitted, thick-walled, 3 or rarely 4-valved, ⅓′—½′ long; pedicel stout, from 1/20′—⅙′ long; seeds ovoid, acute, light brown, nearly ⅛′ in length.
A tree, occasionally 100° high, with a short trunk 5°—6° in diameter, stout spreading branches pendulous at the ends and forming a broad rather open graceful head, and slender terete branchlets light green and glabrous, becoming light yellow before winter, dark or light gray more or less tinged with yellow in their second year, and only slightly roughened by the small 3-lobed leaf-scars. Winter-buds ovoid, acute, with light green lustrous scales, the terminal usually about ⅓′ long and usually two or three times as large as the lateral buds. Bark on young stems light gray-brown, thin, smooth or slightly fissured, becoming on old trees 1½′—2′ thick, dark brown slightly tinged with red, and deeply and irregularly divided into broad connected rounded ridges covered with small closely appressed scales. Wood light brown, with thin nearly white sapwood.
Distribution. Banks of streams; valley of the upper Sacramento River southward through western California to the San Pedro Mártir Mountains, Lower California; most abundant in the San Joaquin Valley, and ascending the western slopes of the southern Sierra Nevada to altitudes of 3000°.
Often planted in southern California as a shade-tree, and for the fuel produced quickly and abundantly from pollarded trees.
In San Bernardino and San Diego Counties, California, generally replaced by the var. pubescens Sarg., differing in its pubescent branchlets and ranging eastward to southwestern Nevada and southern Utah. In southern Arizona and near Silver City, Grant County, New Mexico, represented by the var. Thornberii Sarg., differing from the typical P. Fremontii in the more numerous serratures of the leaves, in the ellipsoidal not ovoid capsules with smaller disk and shorter pedicels, and by the var. Toumeyi Sarg., differing from the type in the shallow cordate base of the leaves, gradually narrowed and cuneate to the insertion of the petiole, and in the larger disk of the fruit (Fig. 124). The var. macrodisca Sarg. with a broad disc nearly inclosing the ellipsoidal fruit is known only in the neighborhood of Silver City.
× Populus Parryi Sarg., a probable hybrid of P. Fremontii and P. trichocarpa, with characters intermediate between those of its supposed parents, grows naturally along Cottonwood Creek on the west side of Owens Lake, Inyo County, and in the neighborhood of Fort Tejon, Kern County, and as a street tree is not rare in San Bernardino, California.
9. [Populus arizonica] Sarg. Cottonwood.
Populus mexicana Sarg., not Wesm.
Leaves deltoid or reniform, gradually or abruptly long-pointed at the acuminate entire apex, truncate or broad-cuneate at the wide base, finely serrate with numerous teeth, as they unfold dark red covered below with pale pubescence, pubescent above, ciliate on the margins, thin, glandular with bright red caducous glands, soon becoming glabrous, at maturity subcoriaceous, bright yellow-green, very lustrous, 1½′—2′ long and broad, with a slender yellow midrib and obscure primary veins; petioles laterally compressed, sparingly villose when they first appear, soon glabrous, 1½′—2′ long; leaves on vigorous leading shoots often rounded at apex, cuneate at base, and often 2′ long and 3′ wide, with petioles often 3′ in length. Flowers: staminate aments dense, cylindric, 1—1½′ long, the pistillate slender, many-flowered, 1½′—2′ long, becoming 3′—4′ long before the fruit ripens; disk of the staminate flower broad-oblong; stamens numerous; disk of the pistillate flower deep cup-shaped, nearly entire; ovary ovoid, rounded at apex, slightly 3 or 4-angled, short-stalked, nearly inclosed in the cup-shaped membranaceous disk. Fruit on short stout pedicels, round-ovoid, buff color, slightly 3 or 4-lobed, deeply pitted, thin-walled, about ¼′ long.
A tree, 50°—70° high, with a trunk occasionally 3° in diameter, gracefully spreading and ascending branches forming a broad open head of wide-spreading branches, and slender often pendulous branchlets, pale green and glabrous or puberulous when they first appear, soon becoming glabrous, and light yellow during their first season. Winter-buds narrow, acute, light orange-brown, puberulous toward the base of the outer scales, the terminal about ¼′ long, and two or three times as large as the much-compressed oblong lateral buds. Bark pale gray or rarely white, and deeply divided into broad flat ridges.
Distribution. Banks of mountain streams; southwestern California (Mill Creek, above Forest Home, San Bernardino Mountains) and southern and central Arizona; widely distributed through northern Mexico (var. Jonesii Sarg.); well distinguished from the other Cottonwoods of the United States by its small fruit.
Often planted as a street tree in the towns of southern Arizona.
10. [Populus texana] Sarg.
Leaves thin, glabrous, broadly ovate, gradually narrowed, long-pointed and acuminate at apex, truncate at base, coarsely crenately serrate below the middle, entire above, 3′—3¼′ long and 2¼′—2½′ wide; petioles slender, compressed, 1½′—2½′ in length. Flowers not seen. Fruit: aments slender, glabrous, 2½′—3′ long; fruit oblong-ovoid, acute, deeply pitted, glabrous, thin-walled, 3-valved, ⅓′ in length; disk slightly lobed; pedicel slender, 1/16′—⅛′ in length; seeds ovoid, acuminate, 1/16′ long.
A tree up to 60° high, with a trunk sometimes 3° in diameter, stout more or less pendulous branches and stout glabrous pale yellow-brown branchlets. Winter-buds acuminate, glabrous.
In cañons and along the streams of northwestern Texas, where it appears to be the only Cottonwood.
11. [Populus McDougallii] Rose.
Leaves broadly ovate, abruptly short-pointed or acute at apex, broadly or acutely cuneate or truncate, or on vigorous shoots rarely slightly cordate at base, finely or often coarsely crenately serrate, bluish green, thin, pubescent on the under sides of the midrib and primary veins early in the season, otherwise glabrous, 1½′—3′ long and broad, with slender midribs and veins; petioles slender, slightly compressed, pubescent early in the season, becoming glabrous, 1½′—2′ in length. Flowers not seen. Fruit: aments glabrous, short-stalked, 2′—2½′ long; fruit ovoid and acute at apex to ellipsoidal and acute or acuminate at ends, glabrous, slightly pitted, thin-walled, 3-valved, 5/12′—½′ long; disk not more than ⅛′ in diameter; pedicels glabrous, ⅛′—⅕′ in length; seeds oblong-ovoid, acuminate, ⅛′ long.
A tree rarely 90°—110° high, usually much smaller, with erect branches and slender branchlets pubescent or puberulous when they first appear, sometimes becoming glabrous during their first season, and sometimes pubescent during two years.
Distribution. Banks of streams and springs, San Bernardino County, California (Cottonwood Springs, Meca, etc.), and eastward to the bottoms of the Colorado River from Clark County, Nevada, to Yuma, Arizona, and probably the only Cottonwood in this arid region.
Often planted as a street tree in the towns of southwestern California and of adjacent Nevada and Arizona.
12. [Populus Wislizenii] Sarg. Cottonwood.
Leaves broadly deltoid, abruptly short- or long-pointed at apex, truncate or sometimes cordate at the broad entire base, coarsely and irregularly crenately serrate except toward the entire apex, coriaceous, glabrous, yellow-green and lustrous, 2′—2½′ long, usually about 3′ wide, with a slender yellow midrib, thin remote primary veins and conspicuous reticulate veinlets; petioles slender, glabrous, 1½′—2′ long; on vigorous shoots often 3½′—4′ long and wide with petioles 3½′—4′ in length. Flowers: aments 2′—4′ long, the pistillate becoming 4′—5′ long before the fruit ripens; scales scarious, light red, divided at the apex into elongated filiform lobes; disk of the staminate flower broad and oblique; stamens numerous, with large oblong anthers and short filaments; disk of the pistillate flower cup-shaped, irregularly dentate, inclosing to the middle the long stalked ovary full and rounded at apex, with 3 broad crenulate lobed stigmas raised on the short branches of the style. Fruit oblong-ovoid, thick-walled, acute, 3 or 4-valved, slightly ridged, buff color, ¼′ long; pedicels slender, ½′—¾′ in length and placed rather remotely on the slender glabrous rachis of the ament.
A large tree, with wide-spreading branches, and stout light orange-colored glabrous branchlets. Winter-buds acute lustrous, puberulous. Bark pale gray-brown, deeply divided into broad flat ridges. Wood used as fuel, for fence-posts and the rafters of Mexican houses.
Distribution. Western Texas through New Mexico to the valley of Grand River, western Colorado (Grand Junction, Mesa County); common in the valley of the Rio Grande in western Texas and New Mexico, and the adjacent parts of Mexico.
Often planted as a shade tree in New Mexico.
13. [Populus Sargentii] Dode.
Populus deltoides var. occidentalis Rydb.
Leaves ovate, usually longer than broad, abruptly narrowed into a long slender entire acuminate point or rarely rounded at apex, truncate or slightly cordate at base, and coarsely crenately serrate, as they unfold slightly villose above and tomentose on the margins, soon glabrous, light green and very lustrous, 3′—3½′ long, 3½′—4′ wide, with a thin midrib, slender primary veins and reticulate veinlets occasionally furnished on the upper side at the insertion of the petiole with one or two small glands; petioles slender, compressed laterally, 2½′—3½′ long. Flowers: aments short-stalked, glabrous, the staminate 2′—2½′ in length, the pistillate becoming 4′—8′ long before the fruit ripens; scales fimbriately divided at apex, scarious, light brown; disk of the staminate flower broad, oblique, slightly thickened on the margins; stamens 20 or more, with short filaments and yellow anthers; disk of the pistillate flower cup-shaped, slightly lobed on the margin; ovary subglobose, with 3 or 4 sessile dilated or laciniately lobed stigmas. Fruit oblong-ovoid, gradually or abruptly narrowed to the blunt apex, thin-walled, about ⅖′ long and three or four times longer than the pedicel; seeds oblong-obovoid, rounded at apex, about 1/16′ in length.
A tree 60°—90° tall with a trunk often 6° or 7° in diameter, erect and spreading branches forming a broad open head, and stout glabrous light yellow often angular branchlets conspicuously roughened by the elevated scars of fallen leaf-stalks. Winter-buds ovoid, acute, with light orange-brown puberulous scales. Bark pale, thick, divided by deep fissures into broad rounded ridges broken into closely appressed scales.
Distribution. The common Cottonwood along the streams in the eastern foothill region of the Rocky Mountains from Saskatchewan to New Mexico, and ranging east to the Dakotas, western Nebraska, Kansas, Oklahoma and Texas.
Often planted as a shade and street tree in the Rocky Mountain states; hardy in Massachusetts.
14. [Populus balsamifera] L. Cottonwood.
Populus angulata Michx. f.
Leaves ovate, longer than broad, abruptly acuminate and often long-pointed at apex, subcordate or rarely truncate at the wide base, finely crenately serrate with glandular teeth, furnished on the upper surface at the insertion of the petiole with two glands, thick, glabrous, green and lustrous on the upper surface, paler below, 5′—7′ long and 4′—5′ wide, with stout midribs and conspicuous primary veins sometimes sparingly pilose below early in the season; petioles much compressed laterally, often more or less tinged with red, 3′—4′ in length. Flowers: aments glabrous, short-stalked, the staminate densely flowered, 1½′—2′ long, ½′—¾′ in diameter, the pistillate slender, sparsely flowered, 3′—3½′ in length; scales scarious, light brown, glabrous, dilated and irregularly divided at apex into filiform lobes; disk of the staminate flower broad, oblique, slightly thickened and revolute on the margins; stamens 60 or more, with short filaments and large dark red anthers; disk of the pistillate flower broad, slightly crenate, inclosing about ⅓′ of the ovoid obtusely pointed ovary, with 3 or 4 sessile dilated laciniately lobed stigmas. Fruit on aments 8′—12′ in length, ellipsoidal, pointed, thin-walled, 3 or 4-valved, ⅓′ long, the disk little enlarged; pedicels ⅙′—¼′ in length; seeds oblong-obovoid, rounded at apex, light brown, about 1/12′ long.
A large tree with massive spreading branches and stout yellow-brown often angular branchlets. Winter-buds resinous, acute, ½′ long with light chestnut brown lustrous scales.
Distribution. Shores of Lake Champlain (Shelburne Point, Chittenden County), Vermont; western New York; Island of the Delaware River above Easton, Northampton County, Pennsylvania; Baltimore County, and Bare Hills, Maryland; northern banks of the Potomac River opposite Plummer’s Island near Washington, D.C.; Artisia, Lowndes County, and Starkville, Oktibbeha County, Mississippi; rare and local.
Populus balsamifera var. virginiana Sarg. Cottonwood.
Populus deltoidea Marsh. at least in part.
Populus nigra β virginiana Castiglioni.
Leaves deltoid to ovate-deltoid, acuminate with entire points, truncate, slightly cordate or occasionally abruptly cuneate at the entire base, crenately serrate above, with incurved glandular teeth, fragrant with a balsamic odor, glabrous, thick and firm, light bright green and lustrous, paler on the lower than on the upper surface, 3′—5′ long and broad, with a stout yellow midrib often tinged with red toward the base, raised and rounded on the upper side, and conspicuous primary veins; petioles slender, pilose at first, soon glabrous, compressed laterally, yellow often more or less tinged with red, 2½′—3½′ long. Flowers and Fruit: as on the type.
A tree, sometimes 100° high, with a trunk occasionally 7°—8° in diameter, divided often 20°—30° above the ground into several massive limbs spreading gradually and becoming pendulous toward the ends, and forming a graceful rather open head frequently 100° across, or on young trees nearly erect above and spreading below almost at right angles with the stem, and forming a symmetrical pyramidal head, and stout branchlets marked with long pale lenticels, terete, or, especially on vigorous trees, becoming angled in their second year, with thin more or less prominent wings extending downward from the two sides and from the base of the large 3-lobed leaf-scars. Winter-buds very resinous, ovoid, acute, the lateral much flattened, ½′ long, with 6 or 7 light chestnut-brown lustrous scales. Bark thin, smooth, light yellow tinged with green on young stems and branches, becoming on old trunks 1½′—2′ thick, ashy gray, and deeply divided into broad rounded ridges broken into closely appressed scales. Wood dark brown, with thick nearly white sapwood, warping badly in drying and difficult to season.
Distribution. Banks of streams, often forming extensive open groves, and toward the western limits of its range occasionally in upland ravines and on bluffs; Province of Quebec and the shores of Lake Champlain, through western New England, western New York, Pennsylvania west of the Allegheny Mountains, and westward to southern Minnesota, North and South Dakota, eastern Nebraska, eastern Kansas, Oklahoma and Texas, and southward through the Atlantic states from Delaware to western Florida, and through the Gulf states to western Texas (Brown County). In the south Atlantic states and the valley of the Lower Ohio River and southward sometimes replaced by a variety with leaves covered above when they unfold with soft white hairs and below with close pubescence more or less persistent during the season especially on the midribs and veins (var. pilosa Sarg.).
Often planted for shelter and ornament on the treeless plains and prairies between the Mississippi River and the Rocky Mountains, and as an ornamental tree in the eastern United States and largely in western and northern Europe.
× Populus canadensis Moench, believed to be a hybrid between the northern glabrous form of P. balsamifera and the European P. nigra L., with several varieties, is cultivated in Europe and occasionally in the United States. The best known of these varieties, × P. canadensis var. Eugenie Schelle, the Carolina Poplar of American nurseries, believed to be a hybrid of the northern Cottonwood with the Lombardy Poplar, has been planted in the United States in immense numbers.
× Populus Jackii Sarg., believed to be a hybrid of the northern Cottonwood with P. tacamahacca, with characters intermediate between those of its supposed parents, grows spontaneously near the mouth of the Chateaugay River and at Beauharnois, Province of Quebec, and at South Haven, Michigan, and is now occasionally cultivated.
15. [Populus Palmeri] Sarg.
Leaves thin, ovate, gradually or abruptly contracted at apex into a narrow acuminate entire point, cuneate or rounded at the broad base, finely serrate with incurved teeth, ciliate on the margins when they unfold, otherwise glabrous, 2½′—5′ long and 1½′—2¼′ wide; petioles slender, glabrous, 1½′—2½′ in length. Flowers not seen. Fruit: aments glabrous, 12—15 cm. long; fruit ovoid, obtuse, slightly pitted, puberulous, thin-walled, 4-valved, ¼′—⅓′ long, the disk deeply lobed; pedicel slender, ¼′—⅓′ in length.
A tree 60° tall, with a straight trunk 3° in diameter, erect smooth pale branches forming an open pyramidal head, the lower branches smaller, horizontal or pendulous, and slender glabrous branchlets light reddish brown early in the season, becoming pale grayish brown in their second year. Bark pale, 3′—4′ thick, deeply divided by wide fissures into narrow ridges.
Distribution. In moist fertile soil near springs, at the base of high chalky bluffs of Nueces Cañon of the upper Nueces River, Uvalde County, growing with Salix nigra var. Lindheimeri, Carya pecan, Morus rubra and Ulmus crassifolia, and at Strawn, Palo Pinto County, Texas.