3. ACACIA Adans.

Fig. 541

Leaves4′—5′ long, glabrous or sometimes slightly puberulous, with slender petioles 1′ long, marked near the middle with an elevated gland, enlarged and slightly glandular at base, and 2—6 pairs of short-stalked 40—80-foliolate pinnæ; stipules foliaceous, ovate or ovate-oblong, acuminate, auriculate and semicordate at base, ½′ long, usually caducous; leaflets obliquely ovate or oblong, obtuse or acute, more or less united at base by the greater development of one of the sides, sessile or short-petiolulate, entire, reticulate-veined, light green, paler on the lower than on the upper surface, ¼′—½′ long, and ⅛′—¼′ wide.Flowersabout ⅓′ long, in heads appearing in Florida early in April, coated before the flowers open with thick pale tomentum, and after the exsertion of the stamens ⅔′ in diameter, on peduncles ¾′—1½′ long, solitary or fascicled in the axils of upper leaves, their bracts and bractlets acute, membranaceous, caducous; calyx 5-toothed, pilose on the outer surface, especially above the middle,1/12′ long, and half as long as the 5-lobed corolla with reflexed lobes; stamens about 20, twice as long as the corolla, united for one fourth of their length into a slender tube.Fruitripening in the autumn and persistent on the branches until after the flowering period of the following year, stipitate, gradually narrowed and acute at the ends, 4′—5′ long, 1′ broad, with a slender stem 1′—2′long, in clusters of 2 or 3 on short peduncles abruptly and conspicuously enlarged at the apex; valves thin and papery, bronze-green when fully grown, becoming dark red-brown, separating slowly from the margins;seedsoval or obovoid, dark brown, lustrous, ½′ long.

A tree, 50°—60° high, with a trunk 2°—3° in diameter, stout spreading branches forming a wide flat head, and glabrous or somewhat pilose conspicuously verrucose branchlets, bright red-brown when they first appear, becoming pale or light reddish brown in their second year.Barkof the trunk of young trees and of the branches smooth, light gray tinged with pink, becoming on old trunks ¼′—½′ thick, dark brown and separating into large plate-like scales.Woodheavy, hard, not strong, tough, close-grained, rich dark brown tinged with red, with nearly white sapwood 1′—1½′ thick, of 4 or 5 layers of annual growth; in Florida occasionally used and valued for boat and shipbuilding.

Distribution.Florida; shores of Bay Biscayne near Miami, and the Everglade Keys, Dade County, common, and on Key Largo, Elliott’s, Plantation, and Boca Chica Keys, not common; on the Bahama Islands and in Cuba.

Trees or shrubs, with slender branches armed with spinescent stipules or infrastipular spines. Leaves alternate on young branchlets and fascicled in earlier axils, bipinnate, with usually small leaflets, persistent. Flowers perfect or polygamous, small, in the axils of minute linear bractlets more or less dilated and often peltate at apex, in globose heads or cylindric spikes on axillary solitary or fascicled peduncles; calyx campanulate, 5 or 6-toothed; petals as many as the divisions of the calyx, more or less united; stamens numerous, usually more than 50, exserted, free or slightly and irregularly united at base, inserted under or just above the base of the ovary; filaments filiform; anthers small, attached on the back, versatile; ovary contracted into a long slender style terminating in a minute stigma. Legume nearly cylindric or flat, indehiscent, continuous or divided within. Seeds transverse, compressed; seed-coat thick, crustaceous, marked on each face of the seed by an oval depression or ring; radicle straight, included, or slightly exserted.

Acacia with more than four hundred species is widely distributed through Australia, where it is most largely represented, tropical and southern Africa, northern Africa, southwestern China, the warmer regions of southern Asia, the islands of the south Pacific, tropical and temperate South America, the West Indies, Central America and Mexico to the southwestern boundaries of the United States where ten or twelve species occur; of these five are arborescent. Acacia is astringent, and many species yield valuable tan bark. Gum arabic is produced by different Old World species; many of the species yield hard heavy durable wood, and some of the Australian Acacias are large and valuable timber-trees. Many species are cultivated for their graceful foliage and handsome fragrant flowers.

The generic name, fromἀκακία, relates to the spines with which the branches are usually armed.

Fig. 542

Leaves2′—4′ long, with 2—8, usually 4 or 5, pairs of pinnæ, generally somewhat puberulous on the short petiole and rachis; in Texas mostly falling at the beginning of winter; pinnæ sessile or short-stalked, remote or close together, with 10—25 pairs of linear acute leaflets tipped with a minute point, unequal at base, sessile or short-petiolulate, glabrous or puberulous, bright green, ⅛′—¼′ long.Flowersbright yellow, very fragrant,1/16′ long, opening during the summer and autumn from the axils of minute clavate pilose bractlets, in heads ⅔′ in diameter, on axillary thin puberulous peduncles, solitary or most often 2 or 3 together and 1′—1½′ in length, with two minute dentate connate bracts forming an involucral cup immediately under the flower-head; calyx about half as long as the petals and like them somewhat pilose on the outer surface; stamens two or three times as long as the corolla; ovary short-stipitate, covered with long pale hairs.Fruitoblong, cylindric or spindle-shaped, thick, turgid, straight or curved, slightly contracted between the seeds, short-stalked, narrowed at apex into a short thick point, 2′—3′ long, ½′—⅔′ broad, dark red-purple, lustrous, and marked by broad light-colored bands along the thickened grooved sutures, the outer coat of the walls thin and papery, inclosing a thick pithy pulp-like substance surrounding the seeds, each in a separate thin-walled compartment;seedsovoid, thick, flattened on the inner surface by mutual pressure, ¼′ long, suspended transversely in 2 ranks on a short straight funicle, light brown, lustrous, and faintly marked by large oval rings.

A tree, 20°—30° high, with a straight trunk 12′—18′ in diameter, separating 6°—8° from the ground into numerous long pendulous branches forming a wide round spreading head, and slender terete or slightly striate angled branchlets, glabrous or at first puberulous, and armed with straight rigid terete spines developed from the persistent stipules and sometimes 1½′ long.Barkof the trunk thin, reddish brown, irregularly broken by long reticulated ridges, exfoliating in large thin scales.Woodheavy, hard, close-grained, rich reddish brown, with thin pale sapwood; in India used for the knees of small vessels and in agricultural implements.

Distribution.Now widely spread by cultivation through the tropical and subtropical regions of the two worlds and probably a native of America from western Texas to northern Chile; growing in Texas apparently naturally in the arid and almost uninhabited region between the Nueces and Rio Grande; naturalized and now covering great areas in the valley of the Guadalupe River near Victoria, Victoria County, Texas.

Largely cultivated in southern Europe for its fragrant flowers used in the manufacture of perfumery, as an ornament of gardens in all warm countries, and in India as a hedge plant.

Fig. 543

Leavesgenerally less than 1′ long, short-petiolate, with a slender puberulous rachis and usually 3 or 4 pairs of pinnæ; early deciduous; pinnæ sessile or short-stalked, remote, with 10—15 pairs of linear somewhat falcate leaflets, acute, tipped with a minute point, subsessile, light green, glabrous,1/20′—1/16′ long.Flowersminute, bright yellow, very fragrant, in the axils of clavate pilose bracts, in heads ¼′—⅜′ in diameter, appearing in March with or just before the unfolding leaves, on clustered or solitary slender puberulous peduncles ½′—¾′ long, and furnished at apex with 2 minute connate bracts; calyx only about one third as long as the corolla, with short puberulous lobes; corolla puberulous at apex, less than half as long as the filaments; ovary covered with short close pubescence.Fruitelongated, linear, slightly compressed, somewhat constricted between the seeds, dark red-brown and cinereo-puberulous, 3′—5′ long and about ¼′ wide;seedsin 1 series, obovoid, compressed, dark red-brown, lustrous, about ¼′ long, faintly marked by large oval rings.

A tree, occasionally 15°—20° high, with a straight trunk 5′—6′ in diameter, stout wide-spreading branches forming an open irregular head, and slender somewhat zigzag slightly angled reddish brown branchlets roughened by numerous minute round lenticels, villose with short pale hairs, and armed with thin terete puberulous spines occasionally ¾′ long; in Texas usually shrubby, with numerous stems forming a symmetric round-topped bush only a few feet high.Barkdark brown or nearly black, and deeply furrowed.

Distribution.Valley of the Rio Cibolo to Eagle Pass on the Rio Grande, Maverick County, Texas; and in northern and southern Mexico, the West Indies, Venezuela, and on the Galapagos Islands; in Texas probably arborescent only on the plains of the Rio Grande near Spofford, Kinney County.

Fig. 544

Leaves3½′—4′ long, with a slender petiole and rachis, villose-pubescent early in the season, becoming nearly glabrous; and 4 or 5 pairs of pinnæ; falling late in the autumn;pinnæ on slender stalks ¼′ in length, with 5—7 pairs of oblong leaflets rounded and apiculate at apex, obliquely rounded at base, short-petiolulate, pointing forward, when they unfold densely villose above and on the margins, and hoary-tomentose below, becoming glabrous, gray-green rather darker above than below, ⅓′ long.Flowerssubsessile, puberulous, in interrupted spikes, ¾′—1′ in length, densely hoary-tomentose when they first appear late in March, on villose peduncles ½′—1′ in length, and furnished near the apex with lanceolate caducous bracts; calyx about half the length of the ovate acute petals ciliate on the margins, about1/12′ long and much shorter than the stamens; ovary stipitate, glabrous.Fruitfully grown in July, stipitate much compressed, rounded and sometimes slightly emarginate at apex, gradually narrowed and obliquely cuneate at base, with much thickened revolute undulate margins, densely pubescent early in the season, becoming puberulous, 5′ or 6′ long, 1¼′—1½′ wide and many-seeded, or nearly orbicular and 1 or 2-seeded;seedsin one series, oval, the two sides unsymmetric, obliquely pointed at base, rounded at apex, compressed, dark chestnut-brown and lustrous, ½′ long and ¼′ wide.

A tree, sometimes 25° high, usually smaller, with slender red-brown branchlets pubescent or puberulous when they first appear, becoming glabrous in their second year, and armed with small curved stipular spines; often a shrub.

Distribution.Texas; creek banks and cañons, near Montell and Uvalde, Uvalde County, and rocky banks of Devil’s River, Valverde County (E. J. Palmer).

Fig. 545

Leaves1′—2′ long, slightly pubescent, especially on the petiole and rachis, with 1—3 pairs of pinnæ, slender petioles 1⅓′ in length, and eglandular or glandular with small convex glands, and linear acute caducous stipules1/16′ long; pinnæ short-stalked, with 2—5 pairs of obovate-oblong leaflets, obliquely rounded and often apiculate at apex, sessile or short-petiolulate, 2 or sometimes 3-nerved, glabrous, or rarely pubescent, reticulate-veined, rigid, bright green and rather paler on the lower surface than on the upper surface, ¼′—⅚′ long.Flowerslight yellow, fragrant, appearing from the end of March to the end of May, on slender pubescent pedicels from the axils of minute caducous bracts, in narrow spikes 1½′ long, often interrupted below the middle, on slender fascicled pubescent or sometimes glabrous peduncles; calyx obscurely 5-lobed, pubescent on the outer surface, half as long as the spatulate petals slightly united at base, and ciliate on the margins; stamens ¼′ long; ovary long-stalked, covered with long pale hairs.Fruitfully grownearly in the summer, deciduous in the autumn, slightly falcate, compressed, stipitate, oblique at base, rounded and short-pointed at apex, 2′—4′ long, 1′—1¼′ wide, with thick straight or irregularly contracted margins and thin papery walls conspicuously marked by narrow horizontal reticulate veins;seedsnarrow-obovoid, compressed, ¼′ long, suspended transversely on a long slender funicle, light brown, marked by large oval depressions.

A tree, occasionally 25°—30° high, with a short trunk 10′—12′ in diameter, spreading branches forming a low wide or irregular head, and branchlets when they first appear somewhat striately angled, glabrous, pale yellow-brown or dark red-brown, turning pale gray in their second year, and armed with occasional stout recurved infrastipular chestnut-brown spines ¼′ long, compressed toward the broad base and sharp-pointed, or rarely unarmed.Barkof the trunk about ⅛′ thick, divided by shallow furrows into broad ridges separating on the surface into thin narrow scales.Woodvery heavy, hard, close-grained, bright clear brown streaked with red and yellow, with thin clear yellow sapwood of 6 or 7 layers of annual growth; valued and largely used as fuel.

Distribution.Valley of the Guadalupe River in the neighborhood of New Braunfels, Comal County, Texas, to the Sierra Madre of Nuevo Leon; most abundant and of its largest size south of the Rio Grande on dry gravelly mesas and foothills.

Fig. 546

Leaves1′—3′ long, pubescent or puberulous, with 1—3 pairs of pinnæ, a short slender petiole furnished near the middle with a minute oblong chestnut-brown gland, and linear caducous stipules1/16′ long; pinnæ short-stalked, with 4—5 pairs of obovate oblique leaflets rounded or truncate at apex and unequally contracted at base into a short petiolule, thick and rigid, 2—3-nerved, inconspicuously reticulate-veined, hoary-pubescent,1/16′—¼′ long.Flowersfragrant, bright creamy yellow, in dense oblong pubescent spikes, on a peduncle ½′—⅔′ long, and fascicled usually 2 or 3 together toward the end of the branches; calyx obscurely 5-lobed, puberulous on the outer surface, half as long as the petals slightly united at base and pale-tomentose on the margins; stamens ¼′ long; ovary long-stalked, covered with long pale hairs.Fruitfully grown at midsummer and hanging unopened on the branches until winter or the following spring, compressed, straight or slightly falcate, obliquely narrowed at base into a short stalk, acute or rounded at apex, more or less contracted between the seeds, 2′—4′ long, ½′—¾′ wide, curling and often contorted when fully ripe, the valves thin and membranaceous, thick-margined, light brown, conspicuously transversely reticulate-veined;seedsnearly orbicular, compressed, dark brown and lustrous, ¼′ in diameter, marked by small oval depressions.

A tree, rarely 30° high, with a trunk 10′—12′ in diameter, numerous spreading branches, and striately angled puberulous or in Texas glabrous pale brown branchlets faintly tinged with red and armed with stout recurved infrastipular spines flat at base, and ¼′ long and broad.Barkof the trunk about ⅛′ thick, furrowed, the surface separating into thin narrow scales.Woodheavy, very hard, strong, close-grained, durable, rich brown or red, with thin light yellow sapwood of 5 or 6 layers of annual growth.

Distribution.Dry gravelly mesas, the sides of low cañons and the banks of mountain streams; valley of the Rio Grande, western Texas, through southern New Mexico and Arizona to southern California, ranging northward in Arizona to the rim of the Grand Cañon of the Colorado River, and to Clark County, Nevada; in northern Mexico, and in Lower California to the eastern base of the San Pedro Mártir Mountains.

Trees or shrubs, with slender unarmed branches. Leaves persistent, abruptly bipinnate, with numerous pinnæ and small leaflets in many pairs, petiolate, the petioles often furnished with a conspicuous gland below the lower pair of pinnæ; stipules minute and caducous, or becoming spinescent and persistent. Flowers minute, white, mostly perfect, sessile or short-pedicellate, in the axils of small peltate bracts villose at apex, in globose many-flowered pedunculate heads, the peduncles in axillary fascicles or in leafless terminal racemes; calyx tubular-campanulate, minutely 5-toothed; petals 5, free, acute or rounded at apex, narrowed at base; stamens 10, free, inserted under the ovary, exserted; filaments filiform; anthers oblong, versatile; ovary stipitate, contracted into a long slender style, with a minute terminal slightly dilated stigma. Legume many-seeded, stipitate, linear, compressed, dehiscent, the valves thickened on the margins, rigid, thin, continuous within, their outer coat thin and papery, dark-colored, the inner rather thicker, woody, pale brown. Seeds obovoid, compressed, transverse, the hilum near the base, suspended on a long slender funicle; seed-coat thin, crustaceous, brown and lustrous; embryo inclosed on its two sides by a thin layer of horny albumen; radicle slightly exserted.

Leucæna with nine or ten species is confined to the warmer parts of America from western Texas to Venezuela and Peru, and to the islands of the Pacific Ocean from New Caledonia to Tahiti, where one species has been recognized. Of the indigenous species found in the territory of the United States, three are arborescent.Leucæna glaucaL., a small tree or shrub, cultivated in all warm countries, and a native probably of tropical America, is now naturalized on Key West, Florida.

The generic name, fromλευχαίνω, refers to the color of the flowers.

Fig. 547

Leaves6′—7′ long and broad, with a slender rachis furnished on the upper side with a single elongated bottle-shaped gland between the stalks of each pair of pinnæ; pinnæ 10—14, remote, short-stalked, with 15—30 pairs of leaflets; stipules gradually narrowed into a long slender point, becoming rigid and spinescent, ⅓′ to nearly ½′ long and persistent for two or three years; leaflets lanceolate, acute or acuminate, often somewhat falcate, nearly sessile or short-petiolulate, full and rounded toward the base on the lower margin, nearly straight on the upper margin, gray-green, ultimately nearly glabrous, ¼′—⅓′ long, about ⅛′ wide, with a narrow midvein and obscure lateral nerves.Flowerson slender pedicels, in heads ¾′—1′ in diameter, on stout peduncles 2′—3′ long furnished at apex with 2 irregularly 3-lobed bracts, and solitary or in pairs; calyx coated with hairs only near the apex, much shorter than the spatulate glabrous more or less boat-shaped petals; ovary villose with a few short scattered hairs.Fruit6′-8′ long, ⅓′—½′ wide, narrowed below into a short stout stipe, acuminate and crowned at apex with the thickened style, ⅓′—¾′ long, cinereo-pubescent until nearly fully grown, becoming nearly glabrous at maturity, much compressed, with narrow wing-like margins;seedsconspicuously notched by the hilum, ½′ long and ⅓′ wide.

A tree, 15°-20° high, with a stem 4′—5′ in diameter, and stout zigzag red-brown branchlets marked by numerous pale lenticels, coated at first with short spreading lustrous yellow deciduous hairs found also on the young petioles and lower surface of the unfolding leaflets, the peduncles of the flower-heads and their bracts.Barkabout ⅜′ thick, dark brown, divided into low ridges and broken on the surface into small closely appressed persistent scales.Woodheavy, hard, close-grained, rich brown streaked with red, with thin clear sapwood.

Distribution.Mountain ravines and the steep banks of streams; western Texas from the valley of the upper San Saba River to that of Devil’s River; and southward into Mexico.

Fig. 548

Leaves3′ or 4′ long and 4′ or 5′ wide, with a slender petiole and rachis and 2-4 pairs of pinnæ 6′-10′ long, remote, long-stalked, with 4-8 pairs of short-stalked leaflets furnished between their stems with a single globose white gland found also occasionally on the upper side of the rachis between the stems of the pinnæ; stipules ovate, gradually narrowed into a long slender tip, ½′ in length, often persistent through the season; leaflets obliquely obovate or elliptic, rounded and apiculate at apex, obliquely rounded or cuneate at the unsymmetric base, entire, short-petiolulate, villose-pubescent like the rachis and petiole when they first appear, soon, glabrous, and at maturity thin, blue-green, ¾′—1′ long and ⅓′—½′ wide, with a slender midrib, and prominent veins extending obliquely toward the apex of the leaflet, those of the lowest pair more prominent and starting from near its base.Flowersshort-stalked in the axil of a peltate bract, its blade produced into a long slender villose tip, appearing continuously from April until October in dense globose heads ¾′ in diameter, on villose bibracteolate axillary, single or fascicled peduncles 1½′—3′ in length; calyx thin, tubular, 5-toothed at apex; petals narrow-oblong, hardly longer than the calyx; stamens 10, shorter than the bract of the flower; anthers glabrous.Fruitsolitary or clustered, on a puberulous peduncle 3′-5′ in length, 6′-10′ long, ⅓′—½′ wide, gradually narrowed below into a stout stipe, the acuminate apex terminating in the thickened persistent style, glabrous and dark reddish brown;seeds⅓′ long and ¼′ wide.

A tree, occasionally 25° high, with a trunk 6′-8′ in diameter, and slender branchlets pubescent when they first appear, becoming puberulous and orange-brown or reddish brown at the end of their first season; more often a shrub.

Distribution.Texas; steep rocky hillsides, and on the summits of limestone bluffs; (Uvalde, Valverde, Kemble, Real and Jeff Davis Counties).

Fig. 549

Leaves4′-7′ long and 3′-4′ wide, with a slender petiole usually marked by a large dark oblong gland between the somewhat enlarged base and the lowest pair of the 30-36 nearly sessile crowded pinnæ, each with 30-60 pairs of leaflets, and minute caducous stipules, when they unfold covered like the peduncles and flower-buds with dense hoary tomentum, and at maturity puberulous on the petiole and rachis; leaflets linear, acute, rather oblique at base by the greater development of the upper side, sessile or veryshort-petiolulate, pale bright green, ⅙′—¼′ long.Flowerssessile, fragrant, in heads ½′ in diameter, appearing in succession as the branches grow from early spring to midsummer, on slender peduncles 1′—1½′ long and fascicled in the axils of upper leaves; calyx one fourth as long as the acute petals and like them pilose on the outer surface; stamens twice as long as the petals; ovary coated with long pale hairs.Fruitconspicuously thick-margined, 4′-14′ long, long-stalked, tipped with a short straight or recurved point, usually in pairs on a peduncle thickened at apex;seeds5/16′ long.

A tree, 50°-60° high, with a straight trunk 18′-20′ in diameter, separating 20°-30° from the ground into slender spreading branches forming a loose round head, and branchlets at first more or less striately grooved and thickly coated with pulverulent caducous tomentum, becoming at the end of a few weeks terete, pale cinnamon-brown and puberulous.Barkabout ¼′ thick, bright cinnamon-brown, and roughened by thick persistent scales.Woodheavy, hard, very close-grained, rich dark brown, with thin clear yellow sapwood of 2 or 3 layers of annual growth; considered valuable, and sometimes manufactured into lumber.

Distribution.Rich moist soil of river banks and the borders of lagoons and small streams; valley of the lower Rio Grande; in Texas only for a few miles near its mouth; more abundant from Matamoras to Monterey in Nuevo Leon; and southward to the neighborhood of the City of Mexico.

Occasionally planted as a shade and ornamental tree in the towns of the lower Rio Grande valley and in New Orleans, Louisiana.

Trees or shrubs, with branches without a terminal bud and armed with geminate supra-axillary persistent spines, and small obtuse axillary buds covered with acute apiculate dark brown scales. Leaves alternate on branches of the year and fascicled in earlier axils, deciduous, usually 2 rarely 3-4-pinnate, with many-foliolate pinnæ; petioles glandular at apex with a minute gland, and tipped with the small spinescent rachis; stipules linear, membranaceous or spinescent, deciduous. Flowers greenish white, nearly sessile, in axillary pedunculate spikes; calyx campanulate, 5-toothed, or slightly 5-lobed, deciduous; petals 5, connate below the middle or ultimately free, glabrous or tomentose on the inner surface toward the apex, sometimes puberulous on the outer surface; stamens 10, free, inserted with the petals on the margin of a minute disk adnate to the calyx-tube, those opposite the lobes of the calyx rather longer than the others; filaments filiform; anthers oblong, versatile, their connective tipped with a minute deciduous gland, the cellsopening by marginal sutures; ovary stipitate, villose; style filiform, with a minute terminal stigma. Legume linear, compressed, or subterete, straight or falcate, or contorted or twisted into a more or less regular spiral, indehiscent; the outer coat thin, woody, pale yellow, inclosing a thick spongy inner coat of sweet pulp containing the seeds placed obliquely and separately inclosed, their envelopes forming nut-like joints. Seeds oblong, compressed, the hilum near the base; seed-coat crustaceous, light brown, lustrous; embryo surrounded by a layer of horny albumen; radicle short, slightly exserted.

Prosopis is distributed in the New World from southern Kansas to Patagonia, and in the Old World is confined to tropical Africa, and to southwestern and tropical Asia. Sixteen or seventeen species have been distinguished. Of the three species found in the territory of the United States two are small trees.

Prosopis produces hard durable wood, particularly valuable as fuel, and the pods are used as fodder.

The generic name is fromπροσωπίς, employed by Dioscorides as a name of the Burdock.

Fig. 550

Leaveswith 2 or rarely 4 pinnæ, and slender terete petioles abruptly enlarged and glandular at base; stipules linear, acute, membranaceous, deciduous.Flowersappearing in successive crops from May to the middle of July, fragrant, about1/12′ long, on short pedicels, in slender cylindric spikes 1½′—4′ long, on stout peduncles ½′—¾′ in length; calyx glabrous or puberulous, about one fourth as long as the narrowly oblong acute petals, glabrous or puberulous on the outer surface and covered on the inner surface toward the apex with hoary tomentum; stamens twice as long as the corolla, the dark-colored connective of the anther-cells furnished at apex with a stalked gland; ovary short-stalked, clothed with silky hairs.Fruitin drooping clusters, linear, at first flat, becoming subterete at maturity, constricted between the 10-20 seeds, straight or falcate, contracted at the ends, 4′—9′ long, ¼′—½′ wide;seedsabout ¼′ long.

A low tree, with a large thick taproot descending frequently to the depth of 40°-50°,and furnished with radiating horizontal roots spreading in all directions and forming a dense mat, a trunk 6′—8′ in diameter, divided a short distance above the ground into many irregularly arranged crooked branches forming a loose straggling head, and slender branchlets at first pale yellow-green, turning darker in their second year, furnished in the axils of the leaves of their first season with short spur-like excrescences covered with chaffy scales, and armed with stout straight terete supra-axillary persistent spines ½′—2′ long, or rarely unarmed; more often a shrub, with numerous stems only a few feet high.Barkof the trunk thick, dark reddish brown, divided by shallow fissures, the surface separating into short thick scales.Woodheavy, close-grained, rich dark brown or sometimes red, with thin clear yellow sapwood; almost indestructible in contact with the soil, and largely used for fence-posts, railway-ties, the underpinnings of buildings, and occasionally in the manufacture of furniture, the fellies of wheels, and the pavements of city streets; the best fuel of the region, and largely made into charcoal. The ripe pods supply Mexicans and Indians with a nutritious food, and are devoured by most herbivorous animals. A gum, resembling gum-arabic, exudes from the stems.

Distribution.Western Texas and eastern New Mexico, and on the island of Jamaica; eastward and westward diverging into two extreme forms. These are

Fig. 551

Leaves8′—10′ long, 2-pinnate, with long slender petioles, the pinnæ 12—20-foliolate; leaflets distant, linear, mostly acute, glabrous, dark green, often 2′ long and ⅛′—¼′ wide.Flowerswith a usually glabrous calyx.Fruitoccasionally conspicuously constricted between the seeds (f.constrictaSarg.).

A round-topped tree, often 20° high, with a trunk a foot in diameter, and long gracefully drooping branches forming a symmetrical round-topped head.

Distribution.Eastern Texas to western Louisiana (near Shreveport, Caddo Parish), western Oklahoma and southern Kansas, and southward into northern Mexico. The common Mesquite of eastern Texas; reappearing with rather shorter and more crowded leaflets in Arizona, southern California, and Lower California.

Fig. 552

Leaves5′—6′ long, often fascicled, 2—4-pinnate, cinereo-pubescent, with short petioles, the pinnæ 12-22-foliolate; leaflets oblong or linear-oblong, obtuse or acute, crowded, pale green, ¼′—½′ long.Flowersin densely-flowered spikes 2′—3′ long; calyx villose.

A tree, often 50° high, with a trunk 2° in diameter, covered with rough dark brown bark, and heavy irregularly arranged usually crooked branches.

Distribution.Dry valleys of southern Arizona and of Sonora.

Fig. 553

Leavescanescently pubescent, 2′—3′ long, with a slender petiole ⅓′—⅔′ in length, and pinnæ 1½′—2′ long and 10—16-foliolate; stipules spinescent, deciduous; leaflets oblong or somewhat falcate, acute, sessile or short-petiolulate, often apiculate, conspicuously reticulate-veined, ⅓′—⅔′ long, ⅛′ wide.Flowersbeginning to open in early spring, and produced in successive crops from the axils of minute scarious bracts, in dense or interrupted cylindric spikes 2′—3′ long; calyx obscurely 5-lobed, pubescent on the outer surface, one third to one fourth as long as the narrow acute petals coated on the inner surface near the apex with thick white tomentum, and slightly puberulous on the outer surface; ovary and young fruit hoary-tomentose.Fruitripening throughout the summer and falling in the autumn, in dense racemes, sessile, twisted with from 12—20 turns into a narrow straight spiral 1′—2′ long;seeds1/16′ long.

A tree, 25°-30° high, with a slender trunk sometimes a foot in diameter, and terete branches canescently pubescent or glabrate when they first appear, becoming glabrous and light red-brown in their third year, and armed with stout spines ⅓′—½′ long.Barkof the trunk thick, light brown tinged with red, separating in long thin persistent ribbon-like scales.Woodheavy, exceedingly hard, close-grained, not strong, light brown, with thin lighter colored sapwood of 6 or 7 layers of annual growth; used as fuel and occasionally for fencing. The sweet, nutritious legumes are valued as fodder.

Distribution.Sandy or gravelly bottom-lands; valley of the Rio Grande in western Texas, and through New Mexico and Arizona to southern Utah and Nevada, and to San Diego County, California, and northern Mexico; attaining its largest size in the United States in the valleys of the lower Colorado and Gila Rivers, Arizona.

Trees or shrubs, with scaly bark, slender unarmed branchlets prolonged by an upper axillary bud, marked by numerous minute pale lenticels, and in their first winter by small elevated horizontal leaf-scars showing the ends of two large fibro-vascular bundles, and small scaly obtuse axillary buds covered by imbricated ovate chestnut-brown scales. Leaves simple, entire, 5—7-nerved with prominent nerves, long-petiolate, deciduous; petioles slender, terete, abruptly enlarged at apex; stipules ovate, acute, small, membranaceous, caducous. Flowers appearing in early spring before or with the leaves on thin jointed pedicels, in simple fascicles or racemose clusters produced on branches of the previous or earlier years, or on the trunk, with small scale-like bracts often imbricated at the base of the inflorescence, and minute bractlets; calyx disciferous, short-turbinate, purplish, persistent, the tube oblique at base, campanulate, enlarged on the lower side, 5-toothed, the short broad teeth imbricated in the bud; corolla subpapilionaceous; petals nearly equal, rose color, oblong-ovate, rounded at apex, unguiculate, slightly auricled on one side of the base of the blade, the upper petal slightly smaller and inclosed in the bud by the wing-petals encircled by the broader slightly imbricated keel-petals; stamens 10, inserted in 2 rows on the margin of the thin disk, free, declinate, those of the inner row opposite the petals and rather shorter than the others; filaments enlarged and pilose below the middle, persistent until the fruit is grown; anthers uniform, oblong, attached on the back near the base; ovary short-stalked, inserted obliquely in the bottom of the calyx-tube; style filiform, fleshy, incurved, with a stout obtuse terminal stigma; ovules 2-ranked, attached to the inner angle of the ovary. Legume stalked, oblong or broad-linear, straight on the upper edge, curved on the lower edge, acute at the ends, compressed, tipped with the thickened remnants of the style, many-seeded, 2-valved, the valves coriaceo-membranaceous, many-veined, tardily dehiscent by the dorsal and often by the wing-margined ventral suture, dark red-purple and lustrous at maturity. Seeds suspended transversely on a slender funicle, ovoid or oblong, compressed, the small depressed hilum near the apex; seed-coat crustaceous, bright reddish brown; embryo surrounded by a thin layer of horny albumen, compressed; cotyledons oval, flat, the radicle short, straight or obliquely incurved, slightly exserted.

Cercis is confined to eastern and western North America, southern Europe, and to southwestern, central and eastern Asia. Of the eight species now distinguished, three occur in North America. Two of these are arborescent.

The generic name is fromκερκίς, the Greek name of the European species, from a fancied resemblance of the fruit to the weaver’s implement of that name.

Fig. 554

Leavesbroad-ovate, acute or acuminate and often abruptly contracted at apex into a short broad point, truncate or more or less cordate at base, entire, glabrous with the exception of axillary tufts of white hairs, or sometimes more or less pubescent below, 3′—5′ long and broad; turning in the autumn before falling bright clear yellow; petioles 2′—5′ in length.Flowers½′ long, on pedicels ⅓′—½′ in length and fascicled 4-8 together; rarely white (var.albaRehdr.).Fruitfully grown in the south by the end of May and at the north at midsummer, and then pink or rose color, 2½′—3½′ long, falling late in the autumn or in early winter;seedsabout ¼′ long.

A tree, sometimes 40°-50° high, with a straight trunk usually separating 10°-12° from the ground into stout branches covered with smooth light brown or gray bark, and forming an upright or often a wide flat head, and slender glabrous somewhat angled branchlets, brown and lustrous during their first season, becoming dull and darker the following year and ultimately dark or grayish brown.Barkof the trunk about ½′ thick and divided by deep longitudinal fissures into long narrow plates, the bright red-brown surface separating into thin scales.Woodheavy, hard, not strong, close-grained, rich dark brown tinged with red, with thin lighter colored sapwood of 8-10 layers of annual growth.

Distribution.Borders of streams and rich bottom-lands, forming, especially west of the Alleghany Mountains, an abundant undergrowth to the forest; valley of the Delaware River, New Jersey, central and southern Pennsylvania southward to northern Florida, northern Alabama and southern Mississippi (Crystal Springs, Copiah County), and westward to southwestern Ontario (Point Pelee, Essex County), and through southern Michigan to southern Iowa, southeastern Nebraska, eastern Kansas, western Oklahoma (Major and Dewey Counties), Louisiana, and the valley of the Brazos River, Texas; and on the Sierra Madre of Nuevo Leon; common and of its largest size in southwestern Arkansas, Oklahoma and eastern Texas, and in early spring a conspicuous feature of the landscape.

Often cultivated as an ornamental tree in the northeastern states, and occasionally in western Europe.

Cercis texensisSarg.


Back to IndexNext