Chapter 7 SALICACE .

Trees or shrubs, with watery juice, alternate simple stalked deciduous leaves with stipules, soft light usually pale wood, astringent bark, scaly buds, and often stoloniferous roots. Flowers appearing in early spring usually before the leaves, solitary in the axils of the scales of unisexual aments from buds in the axils of leaves of the previous year, the male and female on different plants; perianth 0; stamens 1, 2 or many, their anthers introrse, 2-celled, the cells opening longitudinally; styles usually short or none; stigmas 2-4, often 2-lobed.

Fruit a 1-celled 2-4-valved capsule, with 2-4 placentas bearing below their middle numerous ascending anatropous seeds without albumen and surrounded by tufts of long white silky hairs attached to the short stalks of the seeds and deciduous with them; embryo straight, filling the cavity of the seed; cotyledons flattened, much longer than the short radicle turned toward the minute hilum.

The two genera of this family are widely scattered but most abundant in the northern hemisphere, with many species, and are often conspicuous features of vegetation.

CONSPECTUS OF THE GENERA.

Scales of the aments laciniate; flowers surrounded by a cup-shaped often oblique disk; stamens numerous; buds with numerous scales.

1. Populus.

Scales of the aments entire; disk a minute gland-like body; stamens 1, 2 or many; buds with a single scale.

2. Salix.

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 ?′-?′ long.

8. P. Fremontii (G, H).

Branchlets slender; capsule not more than ?′ 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 4?′ long and broad with a prominent midrib, slender primary veins and conspicuous reticulate veinlets; petioles slender, compressed laterally, 1?′-3′ long. Flowers: aments 1?′-2?′ 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 ?′ 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 ?′ 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′-4?′ 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′-2?′ long, becoming 3′-3?′ 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, ?′ 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′-2?′ wide, with a prominent yellow midrib, conspicuously forked veins, and reticulate veinlets; petioles slender, laterally compressed, 1?′-2?′ long. Flowers: aments pubescent, 1?′-2?′ 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 ?′ 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 ?′ 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 ?′-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 2?′-3?′ in length. Flowers: staminate aments broad, densely flowered, 1′ long, erect when the flowers first open, becoming pendulous and 2′-2?′ 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 ?′ 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 ?′ 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 ?′-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, 1?′-3′ wide, with thin veins running obliquely almost to the margins; petioles slender, terete, 1?′ 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 ?′-?′ long, nearly sessile or short-stalked, ?′-?′ 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, ?′ broad; axillary about ?′ 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 ?′-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′-2?′ wide; petioles slender, pubescent, puberulous, pilose or rarely glabrous, 1?′-2′ in length. Flowers: aments stalked, villose-pubescent, the staminate densely flowered, 1?′-2′ long, ?′ thick, the pistillate loosely flowered, 2?′-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, ?′ long and ?′ thick, with 6 or 7 light orange-brown slightly puberulous scales scarious on the margins. Bark ?′-2?′ 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, ?′-1′ wide, or on vigorous shoots occasionally 6′-7′ long, and 1?′ 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, ?′-2?′ long, the pistillate becoming 2?′-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 ?′ long; seeds ovoid or obovoid, rather obtuse, light brown, nearly ?′ 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 ?′-?′ long and nearly twice as large as the axillary buds. Bark ?′-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, ?′-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 ?′ 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 ?′ 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 ?′ 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′-2?′ long, 2?′-3′ wide, with a thin yellow midrib and 4 or 5 pairs of slender veins; petioles flattened, yellow, 1?′-3′ long. Flowers: staminate aments densely flowered, 1?′-2′ long, nearly ?′ 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, ?′-?′ long; pedicel stout, from 1/20′-?′ long; seeds ovoid, acute, light brown, nearly ?′ 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 ?′ 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 1?′-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, 1?′-2′ long and broad, with a slender yellow midrib and obscure primary veins; petioles laterally compressed, sparingly villose when they first appear, soon glabrous, 1?′-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, 1-1?′ long, the pistillate slender, many-flowered, 1?′-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 ?′ 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 ?′ 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′-3?′ long and 2?′-2?′ wide; petioles slender, compressed, 1?′-2?′ in length. Flowers not seen. Fruit: aments slender, glabrous, 2?′-3′ long; fruit oblong-ovoid, acute, deeply pitted, glabrous, thin-walled, 3-valved, ?′ in length; disk slightly lobed; pedicel slender, 1/16′-?′ 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 ca?ons 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, 1?′-3′ long and broad, with slender midribs and veins; petioles slender, slightly compressed, pubescent early in the season, becoming glabrous, 1?′-2′ in length. Flowers not seen. Fruit: aments glabrous, short-stalked, 2′-2?′ long; fruit ovoid and acute at apex to ellipsoidal and acute or acuminate at ends, glabrous, slightly pitted, thin-walled, 3-valved, 5/12′-?′ long; disk not more than ?′ in diameter; pedicels glabrous, ?′-?′ in length; seeds oblong-ovoid, acuminate, ?′ 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′-2?′ long, usually about 3′ wide, with a slender yellow midrib, thin remote primary veins and conspicuous reticulate veinlets; petioles slender, glabrous, 1?′-2′ long; on vigorous shoots often 3?′-4′ long and wide with petioles 3?′-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, ?′ long; pedicels slender, ?′-?′ 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′-3?′ long, 3?′-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, 2?′-3?′ long. Flowers: aments short-stalked, glabrous, the staminate 2′-2?′ 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 ?′ 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, 1?′-2′ long, ?′-?′ in diameter, the pistillate slender, sparsely flowered, 3′-3?′ 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 ?′ 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, ?′ long, the disk little enlarged; pedicels ?′-?′ 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, ?′ 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, 2?′-3?′ 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, ?′ 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 1?′-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, 2?′-5′ long and 1?′-2?′ wide; petioles slender, glabrous, 1?′-2?′ in length. Flowers not seen. Fruit: aments glabrous, 12-15 cm. long; fruit ovoid, obtuse, slightly pitted, puberulous, thin-walled, 4-valved, ?′-?′ long, the disk deeply lobed; pedicel slender, ?′-?′ 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 Ca?on 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.

2. SALIX L. Willow.

Trees or shrubs, with watery juice, scaly bark, soft wood, slender terete tough branchlets often easily separated at the joints, and winter-buds covered by a single scale of 2 coats, the inner membranaceous, stipular, rarely separable from the outer, inclosing at its base 2 minute opposite lateral buds alternate with 2 small scale-like caducous leaves coated with long pale or rufous hairs. Leaves variously folded in the bud, alternate, simple, lanceolate, obovate, rotund or linear, penniveined; petioles sometimes glandular at the apex, and more or less covering the bud, in falling leaving U-shaped or arcuate elevated leaf-scars displaying the ends of 3 small equidistant fibro-vascular bundles; stipules oblique, serrate, small and deciduous, or foliaceous and often persistent, generally large and conspicuous on vigorous young branches, leaving in falling minute persistent scars. Flowers in sessile or stalked aments, terminal and axillary on leafy branchlets; scales of the ament lanceolate, concave, rotund or obovate, entire or glandular-dentate, of uniform color or dark-colored toward the apex, more or less hairy, deciduous or persistent; disk of the flower nectariferous, composed of an anterior and posterior or of a single posterior gland-like body; stamens 3-12 or 1 or 2, inserted on the base of the scale, with slender filaments free or rarely united and usually light yellow, glabrous, or hairy toward the base, and small ovoid or oblong anthers generally rose-colored before anthesis, becoming orange or purple; ovary sessile or stipitate, conic, obtuse to subulate-rostrate, glandular at the base, glabrous, tomentose or villose, with an abbreviated style divided into 2 short recurved retuse or 2-parted stigmas; ovules 4-8 on each of the 2 placentas. Fruit an acuminate 1-celled capsule separating at maturity into 2 recurved valves. Seeds minute, narrowed at the ends, dark chestnut-brown or nearly black; cotyledons oblong.

Salix inhabits the banks of streams and low moist ground, the alpine summits of mountains, and the Arctic and sub-Arctic regions of the northern hemisphere, ranging south in the New World, with a few species, through the West Indies and Central America to Brazil, and the Andes of Chile, and in the Old World to Madagascar, southern Africa, the Himalayas, Burmah, the Malay peninsula, Java, and Sumatra. Of the 160 or 170 species which are now recognized about seventy are found in North America. Of these twenty-four attain the size and habit of trees, the others being small and sometimes prostrate shrubs. Of exotic species, Salix alba L., and Salix fragilis L., important European timber-trees, are now generally naturalized in the northeastern states. The flexible tough branches of several species are used in making baskets; the bark is rich in tannic acid and is used in tanning leather and yields salicin, a bitter principle valuable as a tonic. Many of the species are cultivated as ornamental trees.

Salix is the classical name of the Willow-tree.

CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES

Scales of the flowers deciduous, pale straw color.

Stamens 3 or more.

Leaves green on both surfaces; petioles without glands at the base of the leaves; branchlets easily separable.

Branchlets reddish or grayish purple; leaves mostly narrow-lanceolate; capsule glabrous.

1. S. nigra (A, C, E).

Branchlets yellowish-gray; leaves lanceolate to elliptic-lanceolate; capsule often more or less pubescent.

2. S. Gooddingii (F, G, H).

Leaves (at least when fully grown) pale or glaucous below.

Petioles without glands.

Branchlets easily separable.

Leaves narrow-lanceolate to lanceolate; petioles less than ?′ long.

3. S. Harbisonii (C).

Leaves lanceolate to ovate-lanceolate, caudate; petioles ?′-?′ long.

4. S. amygdaloides (A, B).

Branchlets not easily separable.

Capsules short-stalked (pedicels hardly more than 1/24′ long), ovoid-conic, up to ?′ in length; leaves more or less narrow-lanceolate, petioles glabrous or nearly so.

5. S. Bonplandiana (H).

Capsules long-stalked (pedicels 1/12′-?′ long), more or less acuminate.

Petioles puberulous; leaves lanceolate to ovate-lanceolate; stipules without glands on their inner surface; capsules hardly more than ?′ long.

6. S. l?vigata (G, F).

Petioles hairy-tomentose; leaves lanceolate; stipules glandular on their inner surface; capsules ?′-?′ long.

7. S. longipes (C, D).

Petioles glandular; leaves lanceolate to broadly ovate, caudate; branchlets easily separable.

Leaves distinctly pale or glaucous below, lanceolate to ovate-lanceolate.

8. S. lasiandra (B, G).

Leaves pale green below, ovate to elliptic-lanceolate, abruptly caudate-acuminate.

9. S. lucida (A).

Stamens 2.

Stigmas linear, 4 or 5 times longer than broad.

Leaves linear, hardly more than ?′ long; anthers very small, globose; aments small, in fruit hardly up to ?′ in length.

10. S. taxifolia (H).

Leaves linear-lanceolate to elliptic-lanceolate; up to 2′ in length; anthers ellipsoid; aments longer.

11. S. sessilifolia (B, G).

Stigmas short, hardly 2 or 3 times longer than broad.

Mature leaves covered below with appressed white silky hairs, those of flowering branchlets entire or barely denticulate.

12. S. exigua (B, F, G).

Mature leaves glabrous below, those of flowering branchlets more or less distinctly denticulate.

13. S. longifolia (A, F).

Scales of the flowers persistent, dark brown or fuscous, at least toward the apex (in S. Bebbiana more or less straw-colored or tawny).

Stamens 2.

Ovaries glabrous.

Leaves more or less denticulate or serrate; styles short.

Base of leaf cuneate or rounded.

Leaves acute, oblanceolate to narrowly lanceolate; filaments mostly united below.

14. S. lasiolepis (G).

Leaves mostly acuminate; filaments free.

Branchlets glabrous, lustrous; leaves oblanceolate to narrowly obovate, up to 2′ in length; pedicels ?′-?′ long; stipules small.

15. S. Mackenzieana (A, G).

Branchlets pubescent; leaves narrowly lanceolate to ovate-lanceolate, 4′-6′ long; pedicels 1.5-2.5 mm. long.

16. S. missouriensis (A).

Base of leaf mostly more or less cordate; leaves glabrous; filaments free; pedicels long.

17. S. pyrifolia (A).

Leaves entire, oval to broad-obovate; branchlets villose-pubescent during their first season.

18. S. amplifolia.

Ovaries pubescent (glabrous often in No. 23).

Leaves covered with a soft dense felt-like tomentum, oblong-lanceolate to elliptic-lanceolate.

19. S. alaxensis (B).

Leaves glabrous or more or less villose-pubescent below.

Bracts of the flowers pale or tawny, often reddish at the tip; pedicels up to ?′ in length; leaves elliptic-lanceolate to obovate, reticulate beneath in age, pubescent or glabrate.

20. S. Bebbiana.

Bracts of the flowers brown or fuscous.

Stipules more or less distinctly developed; pedicels several times longer than the short styles.

Leaves elliptic-lanceolate to oblong-elliptic; mostly glabrous in age.

21. S. discolor (A, B, F).

Leaves oblanceolate to cuneate-obovate, covered beneath with short hairs or at maturity with a gray villose-pubescence.

22. S. Scouleriana (A, B).

Stipules usually wanting; pedicels hardly longer than the distinct styles; leaves broad-elliptic to obovate-oblong, more or less grayish villose beneath.

23. S. Hookeriana (B, G).

Stamens usually 1; leaves obovate-oblong, densely covered below with lustrous silvery white silky tomentum.

24. S. sitchensis (B, G).

1. Salix nigra Marsh. Black Willow.

Leaves lanceolate, long-acuminate, often falcate, gradually cuneate or rounded at base, finely serrate, thin bright light green, rather lustrous, with obscure reticulate veins, glabrous or often pubescent on the under side of the midribs and veins and on the short slender petioles, 3′-6′ long, ?′-?′ wide; at the north turning light yellow before falling in the autumn; stipules semicordate, acuminate, foliaceous, persistent, or ovoid, minute, and deciduous. Flowers: aments terminal on leafy pubescent branches, narrowly cylindric, 1′-3′ long; scales yellow, elliptic to obovate, rounded at apex and coated on the inner surface with pale hairs; stamens 3-5, with filaments hairy toward the base; ovary ovoid, short-stalked, glabrous, gradually narrowed above the middle to the apex, with nearly sessile slightly divided stigmatic lobes. Fruit ovoid-conic, short-stalked, glabrous, about ?′ long, light reddish brown.

A tree, usually 30°-40° high, with usually several clustered stout stems, thick spreading upright branches forming a broad somewhat irregular open head, and reddish brown or gray-brown branchlets pubescent when they first appear, soon glabrous, and easily separated at the joints. Winter-buds acute, about ?′ long. Bark 1′-1?′ thick, dark brown or nearly black and deeply divided into broad flat connected ridges separating freely into thick plate-like scales and becoming shaggy on old trunks. Wood light, soft, weak, light reddish brown, with thin nearly white sapwood; now sawed into lumber in the valley of the lower Mississippi River and largely used for packing cases, cellar and barn floors, in furniture, and in the manufacture of toys and other purposes where strength is not important as it does not warp, check or splinter.

Distribution. Low moist alluvial banks of streams and lakes; southern New Brunswick through southern Quebec and Ontario to the region north of Lake Superior, southward to northern and western North Carolina, through the Piedmont region of South Carolina and Georgia to eastern and central Alabama, and westward to southeastern North Dakota, eastern South Dakota, Nebraska, Kansas, the valley of Wichita River, Oklahoma, and central and western Texas to Valverde County.

In southern Arkansas, in Louisiana and in eastern Texas Salix nigra is often replaced by var. altissima Sarg., differing from the type in the more pubescent young branchlets, leaves and petioles, in the more acute base of the leaves and longer petioles, and in its later flowering. A tree sometimes 120 feet high and the tallest of American Willows.

Salix nigra var. Lindheimeri Schn.

Salix Wrightii Sarg., not Anders.

Leaves lanceolate, often slightly falcate, long-pointed and acuminate at apex, cuneate at base, finely glandular-serrate, glabrous, light green on the upper surface, paler below, 4′-5′ long, ?′-?′ wide; petioles pubescent early in the season, becoming glabrous, ?′-?′ in length. Flowers: aments slender, densely villose, 2′-3′ long; scales ovate, acute or rarely rounded at apex, covered with matted white hairs, more abundant on the inner surface; stamens 4 or 5; filaments villose below the middle; ovary ovoid, gradually narrowed to the apex, the 2-lobed stigmas nearly sessile. Fruit ovoid-conic; pedicels about ?′ long.

A tree, 50°-70° high with a trunk often 3° in diameter, large erect spreading branches forming an open irregular head, and slender branchlets light green and slightly pubescent when they first appear, becoming light orange or yellow-brown and lustrous. Bark thick, pale yellow-brown, deeply furrowed, the surface sometimes separating into long plate-like scales.

Distribution. River banks, central and western Texas from Grayson and Dallas Counties and the lower valley of the Brazos River to the valleys of the San Antonio and upper Guadalupe Rivers; in Coahuila, Nuevo Leon and Tamaulipas.

2. Salix Gooddingii Ball.

Salix vallicola Britt.

Leaves lanceolate to narrow elliptic-lanceolate, acute or acuminate, acutely cuneate at base, finely glandular-serrate, often slightly falcate, silky pubescent when they unfold especially below, glabrous and dull green at maturity, 1?′-3′ long, ?′-?′ wide, or on vigorous shoots 5′ or 6′ long and ?′ wide; petioles pubescent, usually becoming glabrous, ?′-?′ in length; stipules orbicular-cordate, coarsely glandular-serrate, pubescent. Flowers: aments pubescent terminal on leafy pubescent branchlets, narrow-cylindric, 1′-2′ long; scales linear-oblanceolate, acute, yellow, hoary tomentose; stamens 3-5; filaments villose toward the base; ovary ovoid-conic, gradually narrowed to the acuminate apex, pubescent or glabrous; style distinct, 2-lobed. Fruit ovoid, acute, light reddish brown, glabrous or pubescent, ?′ long; pedicels glabrous or rarely pubescent, 1/16′-?′ in length.

A tree, 25°-50° high, with slender light orange-colored or grayish glabrous or pubescent easily separable branchlets. Bark rough, thick, deeply furrowed, sometimes nearly black.

Distribution. River banks; Reed Creek, Shasta County, and Red Bluff, Tehama County, California, southward in the interior valleys and on the western foothills of the Sierra Nevada to the mountain valleys in the southern part of the state, and to northern Lower California; eastward through central and southern Arizona; in southeastern Nevada; through southern New Mexico to western Texas (El Paso, El Paso County, and Fort Davis, Jeff Davis County); and southward into northern Mexico.

3. Salix Harbisonii Schn.

Leaves linear-lanceolate, narrow-elliptic or rarely obovate-lanceolate, acute or short-acuminate, obtusely or acutely cuneate at the base, and finely glandular dentate; when the flowers open more or less pubescent especially below or glabrous, and at maturity green on the upper surface, pale on the lower surface, glabrous, 4′ or 5′ long, ?′ broad; petioles villose early in the season, becoming glabrous, ?′ in length, minutely glandular at apex; stipules wanting or minute, semicordate, acute, pubescent on vigorous leading branches and sometimes ?′ long. Flowers: aments terminal on leafy branchlets, 2?′-3′ in length, their rachis villose-pubescent; scales ovate or ovate-oblong, obtuse or acute; stamens usually 5-7, rarely 3-9; filaments densely villose; ovary ovoid, long-acuminate, glabrous, long-stalked; style short, distinct, 2-lobed. Fruit acuminate and long-pointed, acute at base, ?′ long and about as long as its pedicel.

A tree, 30°-50° high, with a trunk 10′ or 12′ in diameter, with often pendulous branches, and slender branchlets more or less densely pubescent or tomentose or nearly glabrous when they first appear, becoming glabrous and dark reddish purple in their second season, and easily separable at the joints; often only a large shrub. Bark thick, deeply furrowed, dark red-brown, separating on the surface into small appressed scales.

Distribution. River banks and the borders of swamps; Dismal Swamp, Norfolk County, Virginia; near Goldsboro, Wayne County, North Carolina; common in the coast region of South Carolina and Georgia, extending up the Savannah River at least as far as Augusta, Richmond County, and through southern Georgia to the valley of the Flint River; swamps near Jacksonville, Duval County, and in the neighborhood of Apalachicola, Florida.

4. Salix amygdaloides Anders. Peach Willow. Almond Willow.

Leaves lanceolate to ovate-lanceolate, frequently falcate, gradually or abruptly narrowed into a long slender point, cuneate or gradually rounded and often unequal at base, finely serrate, slightly puberulous when they unfold, becoming at maturity thin and firm in texture, light green and lustrous above, pale and glaucous below, 2?′-4′ long, ?′-1?′ wide, with a stout yellow or orange-colored midrib, prominent veins and reticulate veinlets; petioles slender, nearly terete ?′-?′ in length; stipules reniform, serrate, often ?′ broad on vigorous shoots, usually caducous. Flowers: aments on leafy branchlets, elongated, cylindric, slender, arcuate, stalked, pubescent or tomentose, 2′-3′ long; scales yellow, sparingly villose on the outer, densely villose on the inner face, the staminate broadly ovate, rounded at the apex, the pistillate oblong-obovate, narrower, caducous; stamens 5-9, with free filaments slightly hairy at the base; ovary oblong-conic, long-stalked, glabrous, with a short style and emarginate stigmas. Fruit globose-conic, light reddish yellow, about ?′ in length.

A tree, sometimes 60°-70° high, with a single straight or slightly inclining trunk rarely more than 2° in diameter, straight ascending branches, and slender glabrous or rarely pilose (f. pilosiuscula Schn.) branchlets marked with scattered pale lenticels, dark orange color or red-brown and lustrous, becoming in their first winter light orange-brown. Winter-buds broadly ovoid, gibbous, dark chestnut-brown, very lustrous above the middle, light orange-brown below, ?′ long. Bark ?′-?′ thick, brown somewhat tinged with red, and divided by irregular fissures into flat connected ridges separating on the surface into thick plate-like scales. Wood light, soft, close-grained, light brown, with thick nearly white sapwood.

Distribution. Banks of streams; Province of Quebec from the neighborhood of Montreal to Winnipeg, and along the fiftieth degree of north latitude to southeastern British Columbia, and to central New York, along the southern shores of Lake Erie, and through northern Ohio to northern Indiana, southwestern Illinois, northern and central Missouri, and to Kansas, northwestern Oklahoma and northwestern Texas; in Colorado, Utah and Nevada to central Oregon and southeastern Washington.

Salix amygdaloides var. Wrightii Schn.

Salix Wrightii Anders.

Leaves lanceolate, gradually acuminate and long-pointed at apex, cuneate at base, finely serrate, occasionally slightly falcate, glabrous, yellow-green on the upper surface, pale on the lower surface, 1?′-2′ long, ?′-?′ wide, and on vigorous summer shoots sometimes 4′ or 5′ long and ?′ wide; petioles slender, glabrous, ?′-?′ in length. Flowers and Fruit as in the species.

A small or large tree best distinguished from S. amygdaloides by the distinctly yellow or yellowish brown glabrous branchlets.

Distribution. Barstow, Ward County, common along the Rio Grande near El Paso and at Belon, El Paso County, and on Amarillo Creek, Potter County, western Texas; through southern New Mexico to the Sacramento Mountains, Otero County.

5. Salix Bonplandiana var. Toumeyi Schn.

Salix Toumeyi. Britt.

Leaves 4′-6′ long, ?′-?′ wide, linear-lanceolate to oblong-lanceolate, acuminate with a long slender point at apex, gradually narrowed and often unequal at the cuneate base, obscurely serrate with glandular teeth, or entire with revolute margins, thick and firm, reticulate-venulose, yellow-green and lustrous above, silvery white below, with a broad yellow midrib; falling irregularly during the winter; petioles stout, grooved, reddish; stipules ovate, rounded, slightly undulate, thin and scarious, ?′-?′ broad, often persistent during the summer. Flowers: aments on leafy branchlets, cylindric, erect, slender, short-stalked, the staminate 1′-1?′ long and somewhat longer than the pistillate; scales broadly obovate, rounded at the apex, light yellow, villose on the outer surface and glabrous or slightly hairy above the middle on the inner surface; stamens usually 3, with free filaments slightly hairy at the base; ovary slender, oblong-conic, short-stalked, glabrous, with nearly sessile much-thickened club-shaped stigmas, sometimes nearly encircled below by the large broad ventral gland. Fruit ovoid-conic, rounded at base, light reddish yellow.

A tree, rarely more than 30° high, with a trunk 12′-15′ in diameter, slender erect and spreading branches often pendulous at the ends, forming a broad round-topped head, and slender glabrous branchlets marked with occasional pale lenticels, light yellow, becoming light or dark red-brown and lustrous, and paler orange-brown in their second year. Winter-buds narrowly ovoid, long-pointed, more or less falcate, bright red-brown, lustrous, ?′ long. Bark ?′-?′ thick, dark brown or nearly black, and deeply divided by narrow fissures into broad flat ridges separating on the surface into closely appressed scales.

Distribution. Banks of streams in the ca?ons of the mountains of central and southern Arizona (Sicamore Ca?on near Flagstaff and Sabino Ca?on, Santa Catalina Mountains); and southwestern New Mexico (ca?on, Saint Louis Mountains, Grant County); in Chihuahua, Sonora and Lower California.

The typical S. Bonplandiana H. B. K. with broader and more coarsely serrate leaves, and flower-aments appearing from July to January from the axils of mature leaves is widely distributed in Mexico and ranges to Guatemala.

6. Salix l?vigata Bebb. Red Willow.

Leaves obovate, narrowed and rounded or acute and mucronate at apex, cuneate at base, with slightly revolute obscurely serrate margins, on sterile branches lanceolate or oblong-lanceolate, acute or acuminate, when they unfold light blue-green and coated on the lower surface with long pale or tawny deciduous hairs, at maturity glabrous, dark blue-green and lustrous above, paler and glaucous below, 3′-7′ long, ?′-1?′ wide, with a broad flat yellow midrib; petioles broad, grooved, puberulous, rarely ?′ long; stipules ovate, acute, finely serrate, usually small and caducous. Flowers: aments cylindric, slender, lax, elongated, 2′-4′ long, on leafy branchlets; scales peltate, dentate at apex, covered with long pale hairs, the staminate obovate, rounded, the pistillate narrower and more or less truncate; stamens usually 5 or 6, with free filaments hairy at the base; ovary conic, acute, rounded below, short-stalked, glabrous, with broad spreading emarginate stigmatic lobes. Fruit elongated, conic, long-stalked, nearly ?′ in length.

A tree, 40°-50° high, with a straight trunk 2° in diameter, slender spreading branches, and slender light or dark orange-colored or bright red-brown glabrous, or in one form tomentose or villose (f. araquipa Jeps.) branchlets; often much smaller, with an average height of 20°-30°. Winter-buds ovoid, somewhat obtuse, pale chestnut-brown, ?′-?′ long. Bark ?′-1′ thick, dark brown slightly tinged with red and deeply divided into irregular connected flat ridges broken on the surface into thick closely appressed scales. Wood light, soft, light brown tinged with red, with thick nearly white sapwood.

Distribution. Banks of streams; western California from the Oregon boundary to the southern borders of the state, ascending to altitudes of 4500° on the western slopes of the southern Sierra Nevada, and eastward to Mohave and Yavapai Counties, Arizona, southeastern Nevada and southwestern Utah.

7. Salix longipes Shuttl.

Salix amphibia Small.

Leaves lanceolate, acuminate or on fertile branches occasionally rounded at the apex, rounded or cuneate at the base, finely serrate, hoary-tomentose early in the season, becoming glabrous above, and pale and glabrous or pubescent below, 2′-4′ long, ?′-?′ wide; petioles hoary-tomentose, ?′-?′ long; stipules minute, ovate, acute, hoary-tomentose, caducous, on vigorous shoots foliaceous, reniform, serrate above the middle, often ?′ in diameter. Flowers: aments terminal on leafy tomentose or glabrous branchlets, narrow-cylindric, 3′ or 4′ long; scales ovate, rounded at the apex, yellow, densely villose-pubescent; stamens 3-7, usually 5 or 6, the filaments hairy toward the base; ovary ovoid-conic, acute, cuneate at the base with a short 2-lobed style, and pedicels up to ?′ in length. Fruit ovoid, often rather abruptly contracted above the middle, ?′ in length.

A tree, 20°-30°, high with a trunk occasionally 12′-18′ in diameter, spreading branches, and glabrous or pubescent red-brown or gray-brown branchlets; or more often a shrub. Bark dark, sometimes nearly black, deeply divided into broad ridges covered by small closely appressed scales.

Distribution. Borders of swamps and streams; coast of North Carolina southward to the Everglade Keys of Florida, ranging westward in Florida to the valley of the Saint Marks River, Wakulla County; in Cuba.

A variety with narrower summer leaves and longer petioles is var. venulosa Schn.

Distribution. Newbern, Craven County, North Carolina, southward near the coast to northern and western Florida, ranging inland in Georgia to the banks of the Savannah River near Augusta, Richmond County, and to Traders Hill, Charlton County; in the neighborhood of New Orleans, Louisiana (Drummond); in southwestern Oklahoma and in western Texas (Blanco, Kendall, Kerr, Bandera and Uvalde Counties).

A variety with obtuse stipules, usually glabrous branchlets and lanceolate or narrow elliptic-lanceolate leaves is distinguished as var. Wardii Schn.

A shrub or small tree.

Distribution. Banks of the Potomac River, District of Columbia, and Alleghany County, Maryland to Natural, Rockbridge, Fairfax and Elizabeth Counties, Virginia; northern Kentucky; northern Tennessee; northeastern Mississippi (near Iuka, Tishamingo County); St. Clair and Madison Counties, Illinois; more abundant in Missouri from Pike County southward to southwestern Kansas, western Arkansas and eastern Oklahoma.

8. Salix lasiandra Benth. Yellow Willow.

Leaves lanceolate to ovate-lanceolate, acuminate and long-pointed at apex, cuneate or rounded at base, often slightly falcate, finely serrate, glabrous, dark green and lustrous above, pale or glaucous below, 1?′-3′ long, about ?′ wide, on vigorous summer shoots often 6′ or 7′ long and 1?′ wide; petioles slender, glabrous, glandular at apex, ?′ in length, or on summer shoots stout and 1′-1?′ long; stipules reniform, caducous. Flowers: aments terminal on leafy puberulous branchlets, narrow-cylindric, 2?′-3′ in length; scales pale pubescent, those of the staminate ament lanceolate-acuminate to obovate and rounded at apex and entire, those of the pistillate ament obovate and usually dentate near the apex; stamens 5-9; filaments hairy below the middle; ovary rather abruptly narrowed above the middle and acuminate, long-stalked; style short with slightly emarginate lobes. Fruit light red-brown, ?′ long; pedicels about 1/16′ in length.

Distribution. Valley of the Yukon River near Dawson, Yukon, Vancouver Island, and southward near the coast of Washington and Oregon, and on the western slope of the Sierra Nevada and on the coast ranges to southern California, ranging from the sea-level to altitudes of 8500° on the southern Sierra Nevada; in New Mexico (Glenwood, Soccoro County, and Santa Fé, Santa Fé County); in Colorado (Buena Vista, Chaffee County, Alice Eastwood). Passing into var. caudata Sudw., distinguished by its caudate-acuminate leaves green on both surfaces, and by its bright yellow or orange-yellow branchlets, and ranging from northeastern Oregon and eastern Washington through Idaho, and from northern Wyoming to southern Colorado, Utah and Nevada.

A variety (var. lancifolia Bebb), differing from the typical S. lasiandra in the gray or rusty villose pubescence covering the branchlets during their first and sometimes their second season and the lower surface of the young leaves, is distributed from Dawson in the valley of the Yukon River southward to the valley of the upper Nesqually River, Washington, to the valley of the Willamette River (Salem, Oregon), to Santa Cruz, Santa Cruz County, and to the San Bernardino Mountains, California.

9. Salix lucida Muehl. Shining Willow.

Leaves ovate-lanceolate, or narrow lanceolate (f. angustifolia Anders.), acuminate and long-pointed at apex, cuneate or rounded at base, finely serrate, 3′-5′ long, 1′-1?′ wide, covered when they unfold with scattered pale caducous hairs, at maturity coriaceous, smooth and lustrous, dark green above, paler below, with a broad yellow midrib, and slender primary veins arcuate and united near the margins; petioles stout, yellow, puberulous, glandular at the apex, with several dark or yellow conspicuous glands, ?′-?′ long; stipules nearly semicircular, glandular-serrate, membranaceous, ?′-?′ wide, often persistent during the summer. Flowers: aments erect, tomentose, on stout puberulous peduncles terminal on short leafy branchlets, the staminate oblong-cylindric, densely flowered, about 1?′ in length, the pistillate slender, elongated, 1?′-2′ long, often persistent until late in the season; scales oblong or obovate, rounded, entire, erose or dentate at apex, light yellow, nearly glabrous or coated on the outer surface with pale hairs, often ciliate on the margins; stamens usually 5, with elongated free filaments slightly hairy at base; ovary narrowly cylindric, long-stalked, elongated, glabrous, with nearly sessile emarginate stigmas. Fruit: cylindric, lustrous, about ?′ long.

A tree, occasionally 25° high, with a short trunk 6′-8′ in diameter, erect branches forming a broad round-topped symmetrical head, and stout glabrous branchlets dark orange color and lustrous in their first season, becoming darker and more or less tinged with red the following year; usually smaller and shrubby in habit. Winter-buds narrowly ovoid, acute, light orange-brown, lustrous, about ?′ long. Bark thin, smooth, dark brown slightly tinged with red.

Distribution. Banks of streams and swamps; Newfoundland to the shores of Hudson's Bay and northwestward to the valley of the Mackenzie River and the eastern base of the Rocky Mountains, southward to southern Pennsylvania, northeastern Iowa, the Turtle Mountains, North Dakota, and eastern Nebraska; very abundant at the north, rare southward; a variety from extreme northeastern New England and adjacent New Brunswick and Quebec (var. intonsa Fernald) is distinguished by its often linear leaves rufous pubescent during the season on the under side of the veins and by its pubescent branchlets; a shrub or tree up to 25°.

10. Salix taxifolia H. B. K.

Leaves linear-lanceolate, narrowed at the ends, acute, slightly falcate, mucronate at the apex, entire or rarely obscurely dentate above the middle, coated as they unfold with long soft white hairs, at maturity pale gray-green, slightly puberulous, ?′-1?′ long, 1/12′-?′ wide, with a slender midrib, thin arcuate veins, and thickened slightly revolute margins; petioles stout, puberulous, rarely 1/12′ long; stipules ovate, acute, scarious, minute, caducous. Flowers: aments densely flowered, oblong-cylindric or subglobose, ?′-?′ long, terminal, or terminal and axillary on the staminate plant, on short leafy branchlets; scales oblong or obovate, rounded or acute and sometimes apiculate at apex, coated on the outer surface with hoary tomentum and pubescent or glabrous on the inner; stamens 2, with free filaments hairy below the middle; ovary ovoid-conic, short-stalked or subsessile, villose, with nearly sessile deeply emarginate stigmas. Fruit cylindric, long-pointed, bright red-brown, more or less villose, short-stalked, about ?′ long.

A tree, often 40°-50° high, with a trunk 18′ in diameter, erect and drooping branches forming a broad open head, and slender branchlets covered during their first season with hoary tomentum, becoming light reddish or purplish brown and much roughened by the elevated persistent leaf-scars. Winter-buds ovoid, acute, dark chestnut-brown, puberulous, about 1/16′ long and nearly as broad as long. Bark of the trunk ?′-1′ thick, light gray-brown, and divided by deep fissures into broad flat ridges covered by minute closely appressed scales.

Distribution. Near El Paso, Texas; southwestern New Mexico, and along mountain streams in southern Arizona; southward through Mexico to Guatemala, and on the Sierra de la Victoria, Lower California.

11. Salix sessilifolia Nutt.

Leaves linear-lanceolate to elliptic-lanceolate, acute or acuminate at apex, cuneate at base, entire or furnished above the middle with a few remote apiculate glandular teeth, bluish green and thickly covered with silky white hairs most abundant on the lower side of the midrib, 1′-2′ long, ?′-?′ wide, or on vigorous summer shoots often 4′ long and 1?′ wide; petioles densely villose-pubescent, 1/16′-?′ in length; stipules ovate to lanceolate, acute, entire or denticulate. Flowers: aments appearing after the leaves, terminal on leafy branchlets, densely hoary-tomentose, 1?′-2?′ long; scales broadly elliptic, acute or rounded at apex, cuneate at base, densely villose-tomentose; stamens 2; filaments villose below the middle; ovary sessile, villose, the stigmas sessile, deeply 2-lobed. Fruit ovoid-acuminate, densely villose, pubescent.

A shrub or small tree occasionally 20° high, with short hairy tomentose branchlets.

Distribution. River banks, southwestern British Columbia; Whitcomb County, Washington, and on the Umpqua and Willamette Rivers, western Oregon. Southward passing into

Var. Hindsiana Anders., a large shrub with numerous stems often 20° high, differing in its more linear or narrow lanceolate usually entire leaves on longer petioles, smaller aments and pubescent, not tomentose, branchlets; and distributed from the valleys of central California to southwestern Oregon. A shrubby form of S. sessilifolia (var. leucodendroides Schn.) with longer and broader leaves is common on the banks of streams in southern California.

12. Salix exigua Nutt.

Leaves lanceolate to oblanceolate, acuminate at the ends, often slightly falcate, minutely glandular-serrate above the middle, bluish green and glabrous above, covered below with appressed silky white hairs, 1?′-3′ long, ?′-?′ wide, or on summer shoots sometimes 4?′ long and 1?′ wide; petioles glabrous, 1/16′ long or less; stipules minute or wanting. Flowers: aments terminal and solitary or terminal and axillary, on leafy glabrous branchlets, 1′-2′ in length; scales hoary pubescent, lanceolate and acute on staminate aments, often wider, obovate and rounded at the apex on pistillate aments; stamens, 2, filaments hairy below the middle; ovary sessile, villose, the stigmatic lobes sessile. Fruit ovoid, acuminate, glabrous.

A shrub with stems 10° or 12° tall, or rarely a tree 25° high, with a trunk 5′ or 6′ in diameter, thin spreading branches forming a round-topped head, and slender glabrous red-brown branchlets. Bark of the trunk thin, longitudinally fissured, grayish brown.

Distribution. Southern Alberta and valley of the Fraser River (Clinton), British Columbia, southward through western Washington and Oregon to San Diego County, California, and southeastern Nevada, and eastward to southern Idaho, central Nevada and western Wyoming (Yellowstone National Park).

Apparently only truly a tree on the banks of the Palouse and other streams of eastern Washington.

Several shrubby forms of S. exigua found in Nevada, Arizona, Colorado, western Nebraska and in Lower California are distinguished.

13. Salix longifolia Muehl. Sand Bar Willow.

Salix fluviatalis Sarg., not Nutt.

Leaves linear-lanceolate, often somewhat falcate, gradually narrowed at the ends, long-pointed, dentate with small remote spreading callous glandular teeth, 2′-6′ long, ?′-?′ wide, when they unfold coated below with soft lustrous silky hairs, at maturity thin, glabrous, light yellow-green, darker on the upper than on the lower surface, with a yellow midrib, slender arcuate primary veins, and slender reticulate veinlets; petioles grooved, ?′-?′ long; stipules ovate-lanceolate, foliaceous, about ?′ long, deciduous. Flowers: aments cylindric on leafy branchlets, pubescent, the staminate about 1′ long, ?′ broad, terminal and axillary, the pistillate elongated, 2′ or 3′ long, about ?′ broad; scales obovate-oblong, entire, erose or dentate above the middle, light yellow-green, densely villose on the outer surface, slightly hairy on the inner; stamens 2, with free filaments slightly hairy at the base; ovary oblong-cylindric, acute, short-stalked, glabrous or pubescent, with large sessile deeply lobed stigmas. Fruit light brown, glabrous or villose, about ?′ long.

A tree, usually about 20° high, with a trunk only a few inches in diameter, spreading by stoloniferous roots into broad thickets, short slender erect branches, and slender glabrous light or dark orange-colored or purplish red branchlets, growing darker after their first season; occasionally 60°-70° high, with a trunk 2° in diameter; often a shrub not more than 5°-6° tall. Winter-buds narrowly ovoid, acute, chestnut-brown, about ?′ long. Bark ?′-?′ thick, smooth, dark brown slightly tinged with red and covered with small closely appressed irregularly shaped scales. Wood light, soft, light brown tinged with red, with thin light brown sapwood.

Distribution. River banks, sand bars and alluvial flats; shores of Lake St. John, Quebec to Manitoba, and southward through western New England to northeastern Virginia, southern Ohio, Indiana and Illinois, western Kentucky, south Tennessee, to the mouth of the Mississippi River, and westward to southwestern South Dakota, southwestern Wyoming, northeastern Colorado, western Kansas and Oklahoma, and northern Texas.

From central and northwestern Texas to northeastern Mexico and southern New Mexico represented by var. angustissima Anders., differing in the absence of a dorsal gland in the male flowers and in the silky pubescence of the young ovary.

In the northern Rocky Mountains region replaced by var. pedunculata Anders., differing from the type in its narrower linear leaves, glabrous ovaries and longer pedicels of the fruit, and ranging from western South Dakota and northwestern Wyoming, through eastern Montana, Saskatchewan, and Alberta, to the valley of the Yukon River in the neighborhood of Dawson.

A shrubby form with leaves densely covered with silky pubescence (var. Wheeleri Schn.) is distributed from New Brunswick to North Dakota, Nebraska and Beckham County, Oklahoma.

14. Salix lasiolepis Benth. Arroyo Willow.

Leaves oblanceolate to lanceolate-oblong, often inequilateral and occasionally falcate, acute or acuminate or rarely rounded at apex, gradually or abruptly cuneate or rounded at base, entire or remotely serrate, pilose above and coated below with thick hoary tomentum when they unfold, at maturity thick and subcoriaceous, conspicuously reticulate-venulose, dark green and glabrous above, pale or glaucous and pubescent or puberulous below, 3′-6′ long, ?′-1′ wide, with a broad yellow midrib and slender arcuate veins forked and united within the slightly thickened and revolute margins; petioles slender, ?′-?′ long; stipules ovate, acute, coated with hoary tomentum, minute and caducous, or sometimes foliaceous, semilunar, acute or acuminate, entire or denticulate, dark green above, pale below, persistent. Flowers: aments erect, cylindric, slightly flexuose, densely flowered, nearly sessile on short tomentose branchlets, 1?′ long, the staminate ?′ thick, and nearly twice as thick as the pistillate; scales oblong-obovate, rounded or acute at the apex, dark-colored, clothed with long crisp white hairs, persistent under the fruit; stamens 2, with elongated glabrous filaments more or less united below the middle; ovary narrow, cylindric acute and long-pointed, dark green, glabrous, with a short style and broad nearly sessile stigmas. Fruit oblong-cylindric, light reddish brown, about ?′ long.

A tree, 20°-35° high, with a trunk 3′-7′ in diameter, slender erect branches forming a loose open head, and stout branchlets coated at first with hoary tomentum, bright yellow or dark reddish brown and puberulous or pubescent during their first year, becoming darker and glabrous in their second season; or often at the north and at high altitudes a low shrub. Winter-buds ovoid, acute, compressed, contracted laterally into thin wing-like margins, light brownish yellow, glabrous or puberulous. Bark on young stems and on the branches thin, smooth, light gray-brown, becoming on old trunks dark, about ?′ thick, roughened by small lenticels and broken into broad flat irregularly connected ridges. Wood light, soft, close-grained, light brown, with thick nearly white sapwood; in southern California often used as fuel.

Distribution. Banks of streams in low moist ground; valley of the Klamath River, California, southward along the foothills of the Sierra Nevada, the central valley, and on the Coast Ranges to southern California; on Santa Catalina Island and on the mountains of southern Arizona; on the Sierra de Laguna, Lower California; occasionally ascending to altitudes of 4000° above the sea.

15. Salix Mackenzieana Barr.

Leaves lanceolate to oblanceolate, or elliptic, long-pointed at apex, cuneate or rounded at base, finely crenately serrate, reddish and pilose with caducous pale hairs when they unfold, at maturity thin and firm in texture, light green above, pale below, 1?′-2′ long, about ?′-?′ wide, on summer shoots, often 4′ long and 1?′ wide, with a slender yellow midrib, arcuate veins, and obscure reticulate veinlets; petioles thin, yellow, about ?′ long; stipules reniform, conspicuously veined, about 1/16′ broad. Flowers: aments densely flowered, glabrous, erect, often more or less curved, about 1?′ long, terminal on short leafy branchlets; scales oblanceolate, acute, dark-colored; stamens 2, with elongated free glabrous filaments; ovary cylindric, long-stalked, elongated, gradually narrowed into a short style, with spreading emarginate stigmas. Fruit ovoid, acuminate, light brown, about ?′ long; pedicels about ?′ in length.

A small tree, with a slender trunk, upright branches forming a narrow shapely head, and slender branchlets marked with scattered lenticels, glabrous or slightly puberulous and often tinged with red when they first appear, soon becoming yellow and lustrous, growing lighter colored in their second year. Winter-buds ovoid, rounded on the back, compressed and acute at the apex, bright orange color, about ?′ long.

Distribution. Borders of streams and swamps; shores of Great Slave Lake southward through the region at the eastern base of the Rocky Mountains to Saskatchewan, northern Idaho, and northwestern Wyoming, and to western Nevada (Lake County; M. S. Bebb), and on the high Sierra Nevada in Calaveras and Mariposa Counties, California (W. L. Jepson).

16. Salix missouriensis Bebb.

Leaves lanceolate or oblanceolate, acuminate and long-pointed at apex, gradually narrowed from above the middle to the cuneate or rounded base, finely glandular-serrate, coated with pale hairs on the lower surface and pilose on the upper surface when they unfold, soon becoming nearly glabrous, at maturity thin and firm, dark green above, pale and often silvery white below, 4′-6′ long, 1′-1?′ wide, with slender veins often united near the margins and connected by coarse reticulate veinlets; petioles stout, pubescent or tomentose, ?′-?′ long; stipules foliaceous, semicordate, pointed or rarely reniform and obtuse, serrate with incurved teeth, dark green and glabrous on the upper side, coated on the lower with hoary tomentum, reticulate-venulose, often ?′ long, deciduous or persistent during the season. Flowers: aments oblong-cylindric, densely flowered, appearing early in February on short leafy branchlets, the staminate 1?′ long and nearly ?′ wide and rather longer than the more slender pistillate aments becoming at maturity lax and 3′-4′ long; scales oblong-obovate, light green, and covered on the outer surface with long straight white hairs; stamens 2, with elongated free glabrous filaments; ovary cylindric, short-stalked, beaked, glabrous, with a short style and spreading entire or slightly emarginate stigmas. Fruit narrow, long-pointed, light reddish brown, ?′ in length; pedicels about half the length of the scales.

A tree, 40°-50° high, with a tall straight trunk 10′-12′ or rarely 18′ in diameter, rather slender upright slightly spreading branches forming a narrow open symmetrical head, and slender branchlets marked by small scattered orange-colored lenticels, light green and coated during their first year with thick pale pubescence, becoming reddish brown and glabrous or puberulous in their second winter. Winter-buds ovoid, round, or flattened, acute at the apex, reddish brown, hoary-tomentose, nearly 1′ long. Bark thin, smooth, light gray, slightly tinged with red, and covered with minute closely appressed plate-like scales. Wood dark red-brown, with thin pale sapwood; durable, used for fence-posts.

Distribution. Deep sandy alluvial bottom-lands of the Missouri River in southwestern Nebraska to western Missouri; through northeastern Kansas and eastern Oklahoma to Cache Creek, Comanche County (G. W. Stevens); and from the neighborhood of St. Louis to southeastern and western Iowa.

17. Salix pyrifolia Anders.

Salix balsamifera Barr.

Leaves ovate to oblong-lanceolate, acute at apex, broad and rounded and usually subcordate at base, finely glandular serrulate, balsamic particularly while young, when they unfold thin, pellucid, red and coated below with long slender caducous hairs, at maturity thin and firm, dark green above, pale and glaucous below, 2′-4′ long, 1′-1?′ wide, with a yellow midrib and conspicuous reticulate veinlets; petioles reddish or yellow, ?′-?′ long; stipules often wanting or on vigorous shoots foliaceous, broadly ovate and acute. Flowers: aments cylindric, 1′-1?′ long, on short leafy branchlets, the staminate 1′-1?′ long and ?′ in diameter and shorter and broader than the pistillate ament; scales obovate, rose-colored, coated with long white hairs; stamens 2, with free filaments and reddish ultimately yellow anthers; ovary narrow-ovoid, long-stalked, gradually contracted above the middle, with a short style and emarginate stigmas. Fruit ovoid-conic, ?′ long, dark orange color; pedicels ?′ in length.

Usually a shrub, often making clumps of crowded slender erect stems generally destitute of branches except near the top, rarely arborescent, with a height of 25°, a trunk 12′-14′ in diameter, erect branches, and comparatively stout reddish brown branchlets becoming olive-green in their second year and marked with narrow slightly raised leaf-scars. Winter-buds acute, much-compressed, bright scarlet, very lustrous, about ?′ long. Bark thin, smooth, dull gray.

Distribution. Cold wet bogs; Newfoundland and the coast of Labrador to the valley of the Saskatchewan and the Mackenzie, and British Columbia, and to northern Maine, New Hampshire, Vermont, New York, Michigan, and northeastern South Dakota; reported to become arborescent only near Fort Kent on the St. John River, Aroostook, Maine.

18. Salix amplifolia Cov.

Leaves oval to broadly obovate, rounded or broadly pointed at apex, gradually or abruptly narrowed at the cuneate base, dentate-serrulate or entire, densely villose when they unfold, with long matted white hairs, at maturity nearly glabrous, pale yellow-green above, slightly glaucous below, 2′-2?′ long, 1′-1?′ wide, with a midrib broad and hoary-tomentose toward the base of the leaf and thin and glabrous above the middle; petioles slender, tomentose. Flowers: aments appearing about the middle of June, stout, pedunculate, tomentose, on leafy branchlets, the staminate 1?′-2′ long and shorter than the pistillate; scales oblanceolate or lanceolate, dark brown or nearly black, covered with long pale hairs; stamens 2, with slender elongated glabrous filaments; ovary ovoid-lanceolate, short-stalked, glabrous or slightly pubescent, gradually narrowed into the elongated slender style crowned with a 2-lobed slender stigma. Fruit ovoid-lanceolate, glabrous, short-stalked, ?′ long.

A tree, occasionally 25° high, with a trunk a foot in diameter, and stout branchlets conspicuously roughened by the large elevated U-shaped leaf-scars, and marked by occasional pale lenticels, coated at first with thick villose pubescence, becoming during their second and third years dark dull reddish purple.

Distribution. Sand dunes on the shores of Yakutat Bay and Disenchantment Bay, Alaska.

19. Salix alaxensis Cov. Feltleaf Willow.

Leaves elliptic-lanceolate to obovate, acute, acuminate or occasionally rounded at apex, gradually narrowed into a short thick petiole, coated above as they unfold with thin pale deciduous tomentum and covered below with a thick mass of snowy white lustrous hairs persistent on the mature leaves, entire, often somewhat wrinkled, dull yellow-green above, 2′-4′ long, 1′-1?′ wide, with a broad yellow midrib; stipules linear-lanceolate to filiform, entire, ?′-?′ long, usually persistent until midsummer. Flowers: aments appearing in June when the leaves are nearly fully grown, stout, erect, tomentose, stalked, on leafy branchlets, the staminate 1′-1?′ long, much shorter than the pistillate; scales oblong-ovate, rounded at apex, dark-colored, and coated with long silvery white soft hairs; stamens 2, with slender elongated filaments; ovary acuminate, short-stalked, covered with soft pale hairs, gradually narrowed into the elongated slender style, with 2-lobed stigmas. Fruit nearly sessile, ovoid, acuminate covered with close dense pale tomentum, ?′ long.

A tree, sometimes 30° high, with a trunk 4′-6′ in diameter, and stout branchlets thickly coated at first with matted white hairs, becoming in their second year glabrous, dark purple, lustrous, marked by large elevated pale scattered lenticels and much roughened by large U-shaped leaf-scars; often shrubby, and in the most exposed situations frequently only a foot or two high, with semiprostrate stems.

Distribution. Coast of Alaska from the Alexander Archipelago to Cape Lisbourne, and eastward to the valley of the Mackenzie River and to the shores of Coronation Gulf; the only arborescent Willow in the coast region west and north of Kadiak Island; attaining its largest size from the Shumagin Islands eastward.

20. Salix Bebbiana Sarg.

Leaves oblong-obovate to oblong-elliptic or lanceolate, acuminate and short-pointed or acute at apex, gradually narrowed and cuneate or rounded at base, remotely and irregularly serrate usually only above the middle, or rarely entire, when they unfold pale gray-green, glabrous or villose, and often tinged with red on the upper surface and coated on the lower with pale tomentum or pubescence, at maturity thick and firm, dull green and glabrous or puberulous above, blue or silvery white and covered with pale rufous pubescence below, especially along the midrib, veins, and conspicuous reticulate veinlets, 1′-3′ long, ?′-1′ wide; petioles slender, often pubescent, reddish, ?′-?′ long; stipules foliaceous, semicordate, glandular-dentate, sometimes nearly ?′ long on vigorous shoots, deciduous. Flowers: aments terminal on short leafy branchlets; scales ovate or oblong, rounded at apex, broader on the staminate than on the pistillate plant, yellow below, rose color at apex, villose with long pale silky hairs, persistent under the fruit; staminate aments cylindric, obovoid, narrowed at base, densely flowered, ?′-1′ long, ?′-1′ thick; pistillate aments oblong-cylindric, loosely flowered, 1′-1?′ long, ?′ thick; stamens 2, with free glabrous filaments; ovary cylindric, villose; with long silky white hairs, gradually narrowed at apex, with broad sessile entire or emarginate spreading yellow stigmas; pedicel villose, about ?′ in length, and about as long as the scale. Fruit elongated-cylindric, gradually narrowed into a long thin beak, and raised on a slender stalk sometimes ?′ long.

A bushy tree, occasionally 25° high, with a short trunk 6′-8′ in diameter, stout ascending branches forming a broad round head, and slender branchlets coated at first with hoary deciduous tomentum, varying during their first winter from reddish purple to dark orange-brown, marked by scattered raised lenticels and roughened by conspicuous elevated leaf-scars, growing lighter-colored and reddish brown in their second year; usually much smaller and often shrubby in habit. Bark thin, reddish or olive-green or gray tinged with red, and slightly divided by shallow fissures into appressed plate-like scales. Winter-buds oblong, gradually narrowed and rounded at apex, full and rounded on the back, bright light chestnut-brown, nearly ?′ long.

Distribution. Borders of streams, swamps, and lakes, hillsides, open woods and forest margins, usually in moist rich soil; valley of the St. Lawrence River to the shores of Hudson's Bay, the valley of the Mackenzie River within the Arctic Circle, Cook Inlet, Alaska, and the coast ranges of British Columbia, forming in the region west of Hudson's Bay almost impenetrable thickets, with twisted and often inclining stems; common in all the northern states, ranging southward to Pennsylvania and westward to Minnesota and through the Rocky Mountain region from western Idaho and northern Montana to northern North Dakota, eastern South Dakota, northeastern and central Iowa, and western Nebraska, and southward through Colorado to northern Arizona; ascending as a low shrub in Colorado to an altitude of 10,000°.

21. Salix discolor Muehl. Glaucous Willow.

Leaves lanceolate to elliptic, gradually narrowed at the ends, remotely crenulate-serrate, as they unfold thin, light green often tinged with red, pubescent above and coated with a pale tomentum below, at maturity thick and firm, glabrous, conspicuously reticulate-venulose, bright green above, glaucous or silvery white below, 3′-5′ long, ?′-1?′ wide, with a broad yellow midrib and slender arcuate primary veins; petioles slender, ?′-1′ long; stipules foliaceous, semilunar, acute, glandular-dentate, about ?′ long, deciduous. Flowers: aments appearing late in winter or in very early spring, erect, terminal on short scale-bearing branchlets coated with thick white tomentum, oblong-cylindric, about 1′ long and ?′ thick, the staminate soft and silky before the flowers open and densely flowered; scales oblong-obovate, dark reddish brown toward the apex, covered on the back with long silky silvery white hairs; stamens 2, with elongated glabrous filaments; ovary oblong-cylindric, narrowed above the middle, villose, with a short distinct style and broad spreading entire stigmas; pedicel glabrous, about twice the length of the scale. Fruit cylindric, more or less contracted above the middle, long-pointed, light brown, coated with pale pubescence.

A tree, rarely more than 25° high, with a trunk about 1° in diameter, stout ascending branches forming an open round-topped head, and stout branchlets marked by occasional orange-colored lenticels, dark reddish purple and coated at first with pale deciduous pubescence; more often shrubby, with numerous tall straggling stems. Winter-buds semiterete, flattened and acute at the apex, about ?′ long, dark reddish purple and lustrous. Bark ?′ thick, light brown tinged with red, and divided by shallow fissures into thin plate-like oblong scales. Wood light, soft, close-grained, brown streaked with red, with lighter brown sapwood.

Distribution. Moist meadows and the banks of streams and lakes; Nova Scotia to Manitoba, and southward to Delaware, southern Indiana and Illinois, eastern and southwestern Iowa, the Black Hills of South Dakota, and northeastern Missouri; common.

A form of Salix discolor with more densely flowered and more silvery pubescent aments is described as var. eriocephala Schn. and a form with loosely flowered aments with less tomentose fruits with longer styles and with narrower leaves as var. prinoides Schn.

22. Salix Scouleriana Barr. Black Willow.

Salix Nuttallii Sarg.

Leaves oblong-obovate to elliptic, acute or abruptly acuminate with a short or long-pointed apex, gradually narrowed and cuneate at the often unsymmetrical base, entire or remotely and irregularly crenately serrate, thin and firm, dark yellow-green and lustrous above, pale or glaucous and glabrous or pilose below, 1?′-4′ long, ?′-1?′ wide, with a broad yellow pubescent midrib and slender veins forked and arcuate within the slightly thickened and revolute margins and connected by conspicuous reticulate veinlets; petioles slender, puberulous, ?′-?′ in length; stipules foliaceous, semilunar, glandular-serrate, ?′-?′ long, caducous. Flowers: aments appearing before the leaves, oblong-cylindric, erect, nearly sessile on short tomentose scale-bearing branchlets, the staminate about 1′ long and rather more than ?′ thick, the pistillate 1?′ long, about 5/12′ thick; scales oblong, narrowed at the ends, dark-colored, covered with long white hairs, persistent under the fruit; stamens 2, with free glabrous filaments; ovary cylindric, short-stalked, with a distinct style and broad emarginate stigmas; pedicels less than half the length of the scale, villose. Fruit oblong-ovoid, acuminate, light reddish brown, pale pubescent, about ?′ long.

A tree, occasionally 30° high, with a short trunk rarely exceeding 1° in diameter, slender pendulous branches forming a rather compact round-topped shapely head, and stout branchlets marked by scattered yellow lenticels, coated when they first appear with pale early deciduous pubescence, becoming bright yellow or dark orange color, and in their second year dark red-brown and much roughened by the conspicuous leaf-scars; or more often a shrub. Winter-buds ovoid, acute, nearly terete or slightly flattened, with narrow lateral wing-like margins, light or dark orange color, glabrous or pilose at the base, about ?′ long. Bark thin, dark brown slightly tinged with red, and divided into broad flat ridges. Wood light, soft, close-grained, light brown tinged with red, with thick nearly white sapwood.

Distribution. Cook's Inlet, coast of Alaska, and valley of the Yukon River near Dawson southward through western British Columbia to northern California, ranging eastward through Washington and northwestern Oregon to northern Idaho and Montana.

From central California to San Bernardino County represented by the variety crassijulis Andr. (S. brachystachys Benth.) with shorter and broader obovate leaves rounded at apex, pubescent and tomentose branchlets and larger pubescent winter-buds. A tree sometimes 70° high with a trunk often 2?° in diameter.

On the high Sierra Nevada eastward to the eastern ranges of the Rocky Mountains of Colorado and to northern New Mexico, northern Wyoming and the Black Hills of South Dakota represented by the var. flavescens Schn. A shrub or rarely a small tree with obovate rounded yellowish leaves and branchlets.

23. Salix Hookeriana Barr.

Leaves oblong to oblong-obovate, acute or abruptly acuminate, or rarely rounded and frequently apiculate at apex, gradually narrowed and cuneate or rounded at base, coarsely crenately serrate, especially those on vigorous shoots, or entire, when they unfold villose with pale hairs, or tomentose above and clothed below with silvery white tomentum, at maturity thin and firm, bright yellow-green and lustrous, nearly glabrous or tomentose on the upper surface, pale and glaucous and tomentose or pubescent on the lower surface, especially along the midrib and slender arcuate primary veins and conspicuous reticulate veinlets, 2′-6′ long, 1′-1?′ wide; petioles stout, tomentose, ?′-?′ long. Flowers: aments oblong-cylindric, erect, rather lax, often more or less curved, about 1?′ long, on short tomentose scale-bearing branchlets, the staminate ?′ thick and rather thicker than the pistillate; scales oblong-obovate, yellow, coated with long pale hairs, the staminate rounded above and rather shorter than the more acute scales of the pistillate ament persistent under the fruit; stamens 2, with free elongated glabrous filaments; ovary conic, glabrous, stalked, with a slender stalk about one third as long as the scale, gradually narrowed above, with a slender elongated bright red style and broad spreading entire stigmas. Fruit oblong-cylindric, narrowed above, about ?′ long.

A tree, occasionally 30° high, with a trunk about 1° in diameter, and stout branchlets marked by large scattered orange-colored lenticels, covered during their first season with hoary tomentum and rather bright or dark red-brown and pubescent in their second summer; more often shrubby, with numerous stems 4′-8′ thick and 15°-20° high; frequently a low bush, with straggling almost prostrate stems. Winter-buds ovoid, acute, nearly terete, dark red, coated with pale pubescence, about ?′ long. Bark nearly ?′ thick, light red-brown, slightly fissured and divided into closely appressed plate-like scales. Wood light, soft, close-grained, light brown tinged with red, with thin nearly white sapwood.

Distribution. Borders of salt marshes and ponds and sandy coast dunes; Vancouver Island southward along the shores of Puget Sound and the Pacific Ocean to southern Oregon.

24. Salix sitchensis Sanson.

Leaves oblong-obovate to oblanceolate, entire or minutely glandular dentate, acute or acuminate, or rounded and short-pointed, or rounded at apex, gradually narrowed and cuneate at base, when they unfold pubescent or tomentose on the upper surface, and coated on the lower with lustrous white silky pubescence or tomentum persistent during the season or sometimes deciduous from the leaves of vigorous young shoots, at maturity thin and firm, dark green, lustrous and glabrous above, with the exception of the pubescent midrib, 2′-5′ long, ?′-1?′ wide, with conspicuous slender veins arcuate and united within the margins and prominent reticulate veinlets; petioles stout, pubescent, rarely ?′ long; stipules rarely produced, foliaceous, semilunar, acute or rounded at apex, glandular-dentate, coated below with hoary tomentum, often ?′ long, caducous. Flowers: aments cylindric, densely flowered, erect on short tomentose leafy branchlets, the staminate 1?′-2′ long and ?′ thick, the pistillate 2?′-3′ long, and ?′ thick; scales yellow or tawny, the staminate oblong-obovate, rounded at the apex, covered with long white hairs, much longer than the more acute pubescent scales of the pistillate ament; stamen 1, with an elongated glabrous filament, or very rarely 2, with filaments united below the middle or nearly to the apex; ovary short-stalked, ovoid, conic, acute, pubescent and gradually narrowed into the elongated style, with entire or slightly emarginate short stigmas. Fruit ovoid, narrowed above, light red-brown, pubescent about ?′ long.

A much-branched tree, occasionally 25°-30° high, with a short contorted often inclining trunk sometimes 1° in diameter, and slender brittle branchlets coated at first with hoary tomentum, pubescent and tomentose and dark red-brown or orange color during their first winter, becoming darker, pubescent or glabrous, and sometimes covered with a glaucous bloom in their second season; more often shrubby and 6°-15° tall. Winter-buds acute, nearly terete, light red-brown, pubescent or puberulous, about ?′ long. Bark about ?′ thick and broken into irregular closely appressed dark brown scales tinged with red. Wood light, soft, close-grained, pale red, with thick nearly white sapwood.

Distribution. Banks of streams and in low moist ground; Cook Inlet and Kadiak Island, Alaska, southward in the neighborhood of the coast to Santa Barbara, California; on the Marble Creek of the Kaweah River at 6900° altitude (f. Ralphiana Jeps.)