Part 79

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

5. PROSOPIS L. Mesquite.

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 cells opening 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 from προσωπίς, employed by Dioscorides as a name of the Burdock.

CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES.

Legume compressed or ultimately convex; pinnæ 12—22-foliolate. 1. P. juliflora (C, E, G, H). Legume thick, spirally twisted; pinnæ 10—16-foliolate. 2. P. pubescens (E, F, G, H).

1. Prosopis juliflora DC. Mesquite. Honey Locust.

Leaves with 2 or rarely 4 pinnæ, and slender terete petioles abruptly enlarged and glandular at base; stipules linear, acute, membranaceous, deciduous. Flowers appearing in successive crops from May to the middle of July, fragrant, about 1/12′ 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. Fruit in 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; seeds about 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. Bark of the trunk thick, dark reddish brown, divided by shallow fissures, the surface separating into short thick scales. Wood heavy, 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

Prosopis juliflora var. glandulosa Cock.

Leaves 8′—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. Flowers with a usually glabrous calyx. Fruit occasionally conspicuously constricted between the seeds (f. _constricta_ Sarg.).

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.

Prosopis juliflora var. velutina Sarg.

Leaves 5′—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. Flowers in 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.

2. Prosopis pubescens Benth. Screw Bean. Screw Pod Mesquite.

Leaves canescently 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. Flowers beginning 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. Fruit ripening 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; seeds 1/16′ 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. Bark of the trunk thick, light brown tinged with red, separating in long thin persistent ribbon-like scales. Wood heavy, 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.

6. CERCIS L.

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 from κερκίς, the Greek name of the European species, from a fancied resemblance of the fruit to the weaver’s implement of that name.

CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES.

Flowers in sessile clusters; leaves ovate, acute, cordate or truncate at base. 1. C. canadensis (A, C). Flowers fascicled or slightly racemose; leaves reniform. 2. C. reniformis (C).

1. Cercis canadensis L. Redbud. Judas-tree.

Leaves broad-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. Flowers ½′ long, on pedicels ⅓′—½′ in length and fascicled 4-8 together; rarely white (var. _alba_ Rehdr.). Fruit fully 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; seeds about 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. Bark of the trunk about ½′ thick and divided by deep longitudinal fissures into long narrow plates, the bright red-brown surface separating into thin scales. Wood heavy, 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.

2. Cercis reniformis Engl. Redbud.

_Cercis texensis_ Sarg.

Leaves reniform, when they unfold light green and slightly pilose, and at maturity subcoriaceous, dark green and lustrous on the upper surface, paler, glabrous or pubescent on the lower surface, and 2′—3′ in diameter; petioles 1½′—2′ in length. Flowers about ½′ long, on slender pedicels ½′—¾′ in length and fascicled in sessile clusters, or occasionally racemose. Fruit 2′—4′ long, ½′—1′ wide; seeds ¼′ long.

A slender tree, occasionally 20° or rarely 40° high, with a trunk 6′-12′ in diameter, and glabrous branchlets marked by numerous minute white lenticels, light reddish brown during their first and second years, becoming dark brown in their third season; more often a shrub, sending up numerous stems and forming dense thickets only a few feet high. Bark of the trunk and branches thin, smooth, light gray. Wood heavy, hard, close-grained brown streaked with yellow, with thin lighter colored sapwood of 5 or 6 layers of annual growth.

Distribution. Limestone hills and ridges; neighborhood of Dallas, Dallas County, Texas to the Sierra Madre of Nuevo Leon; common in the valley of the upper Colorado River, Texas; of its largest size on the mountains of northeastern Mexico.

7. GYMNOCLADUS Lam.

Trees, with stout unarmed blunt branchlets with a thick pith, prolonged by axillary buds, rough deeply fissured bark, thick fleshy roots, and minute buds depressed in pubescent cavities of the bark, 2 in the axil of each leaf, superposed, remote, the lower and smaller sterile and nearly surrounded by the enlarged base of the petiole, their scales 2, ovate, rounded at apex, coated with thick dark brown tomentum, infolded one over the other, accrescent with the young shoots. Leaves deciduous, unequally bipinnate; pinnæ many-foliolulate, with 1 or 2 pairs of the lowest pinnæ reduced to single leaflets; pinnæ and leaflets usually alternate; leaflets thin, ovate, entire, petiolulate; stipules foliaceous, early deciduous. Flowers regular, diœcious, greenish white, long-pedicellate, the slender pedicels from the axils of long lanceolate scarious caducous bracts, bibracteolate near the middle; staminate flowers in a short terminal racemose corymb; pistillate flowers in elongated terminal racemes, on pedicels much longer than those of the staminate flowers; calyx tubular, elongated, 10-ribbed, lined with a thin glandular disk, 5-lobed, the lobes, lanceolate, acute, nearly equal, erect; petals 4 or 5, oblong, rounded or acute at apex, pubescent, as long as the calyx-lobes or rather longer and twice as broad, inserted on the margin of the disk, spreading or reflexed; stamens 10, free, inserted with the petals, erect, included; filaments filiform, pilose, those opposite the petals shorter than the others; anthers oblong, uniform, small and sterile in the pistillate flower; ovary sessile or slightly stipitate, acute; styles short, erect, obliquely dilated into 2 broad lobes stigmatic on their inner surface, rudimentary or 0 in the sterile flower; ovules numerous, suspended from the angle opposite the posterior petals. Legume oblong, subfalcate, turgid or slightly compressed, several-seeded, 2-valved, tardily dehiscent, the thin tough woody valves thickened on the margins into narrow wings, pulpy between the seeds. Seeds ovoid or slightly obovoid, suspended by a long slender funicle; seed-coat thick, bony, brown and opaque, of 3 layers; embryo surrounded by a thin layer of horny albumen; cotyledons ovate, orange-colored, thick and fleshy, the radicle short, erect.

Gymnocladus, with two species, is confined to eastern North America and to central China.

Gymnocladus is slightly astringent and purgative, and the detersive pulp surrounding the seeds of the Asiatic species is used in China as a substitute for soap.

The generic name, from γυµνός and κλάδος, relates to the stout branchlets destitute of spray.

1. Gymnocladus dioicus K. Koch. Kentucky Coffee-tree. Mahogany.

Leaves 1°—3° long, 18′—24′ wide, obovate, 5—9 pinnate, the pinnæ 6—14-foliolate, covered when they unfold with hoary tomentum except on the upper surface of the ovate acute leaflets, often mucronate, especially while young, cuneate or irregularly rounded at base, pink at first, soon becoming bronze-green and lustrous, glabrous on the upper surface with the exception of a few scattered hairs along the midrib, and at maturity thin, obscurely veined, dark green above, pale yellow-green and glabrous below, with the exception of a few short hairs scattered along the narrow midrib, 2′—2½′ long and 1′ wide, or those replacing the lowest or occasionally the 2 lower pairs of pinnæ sometimes twice as large; turning bright clear yellow in the autumn before falling; petioles abruptly and conspicuously enlarged at base, at first hoary-tomentose, becoming glabrous at maturity; stipules lanceolate or slightly obovate, glandular-serrate toward the apex, ⅓′ long. Flowers: inflorescence of the staminate tree 3′—4′ long, the lower branches usually 3 or 4-flowered; inflorescence of the pistillate tree 10′—12′ long, the flowers on stout pedicels 1′—2½′ long or twice to five times as long as those of the staminate flowers; flowers hoary-tomentose in the bud; calyx ⅔′ long, covered on the outer surface when the flowers open with pale hairs and on the inner surface with hoary tomentum; petals keeled, pilose on the back, slightly grooved, tomentose on the inner surface; anthers bright orange color; ovary hairy. Fruit 6′—10′ long, 1½′—2′ wide, dark red-brown, covered with a glaucous bloom, on stout stalks 1′—2′ in length, remaining unopened on the branches through the winter; seeds separated by a thick layer of dark-colored sweet pulp, ¾′ long.

A tree, 75°—110° high, with a trunk 2°—3° in diameter, usually dividing 10°—15° from the ground into 3 or 4 principal stems spreading slightly and forming a narrow round-topped head, or occasionally sending up a tall straight shaft destitute of branches for 70°—80°, and branchlets coated when they first appear with short dense pubescence faintly tinged with red, bearing at their base the conspicuous orange-green obovate pubescent bud-scales, ¼′—⅓′ thick at the end of their first season, very blunt, dark brown, often slightly pilose, marked by orange-colored lenticels, and roughened by the large pale broadly heart-shaped leaf-scars displaying the ends of 3 or 4 conspicuous fibro-vascular bundles. Bark of the trunk ¾′—1′ thick, deeply fissured, dark gray tinged with red, and roughened by small persistent scales. Wood heavy although not hard, strong, coarse-grained, very durable in contact with the soil, rich light brown tinged with red, with thin lighter colored sapwood of 5 or 6 layers of annual growth; occasionally used in cabinet-making and for fence-posts, rails, and in construction. The seeds were formerly used as a substitute for coffee; a decoction of the fresh green pulp of the unripe fruit is used in homœopathic practice.

Distribution. Bottom-lands in rich soil; central and western New York and Franklin County, Pennsylvania, through southern Ontario and southern Michigan to southeastern Minnesota, northeastern and southern Iowa, southeastern South Dakota, eastern and northeastern Nebraska, eastern Kansas, southwestern Arkansas and northeastern Oklahoma (with isolated stations in Woods and Custer Counties and in the western parts of Cimarron County); in Eastern Kentucky, and western and middle Tennessee; nowhere common.

Occasionally cultivated in the gardens and parks of the eastern United States, and of northern and central Europe.

8. GLEDITSIA L.

Trees, with furrowed bark, slender terete slightly zigzag branchlets thickened at the apex and prolonged by axillary buds, thick fibrous roots, the trunk and branches often armed with stout simple or branched spines or abortive branchlets developed from supra-axillary or adventitious buds imbedded in the bark. Winter-buds minute, 3 or 4 together, superposed, the 2 or 3 lower without scales and covered by the scar left by the falling of the petiole, the upper larger, nearly surrounded by the base of the petiole and covered by small scurfy scales. Leaves long-petiolate, often fascicled in earlier axils, abruptly pinnate or bipinnate, the pinnæ increasing in length from the base to the apex of the leaf, the lowest sometimes reduced to single leaflets; deciduous; leaflets thin, their margins irregularly crenate, without stipels; stipules minute, caducous. Flowers regular, polygamous, minute, green or white on short pedicels, in axillary or lateral simple or fascicled racemes, with minute scale-like caducous bracts; calyx campanulate, lined with the disk, 3—5-lobed, the narrow lobes nearly equal; petals as many as the lobes of the calyx, nearly equal; stamens 6—10, inserted with the petals on the margin of the disk, exserted; filaments free, filiform, erect; anthers uniform, much smaller and abortive in the pistillate flower; ovary subsessile, rarely bicarpellary, rudimentary or 0 in the staminate flower; styles short; stigma terminal, more or less dilated, often oblique; ovules 2 or many, suspended from the angle opposite the posterior petal. Legume compressed, many-seeded, elongated, straight and indehiscent, or 1—3-seeded, ovoid and tardily dehiscent. Seeds transverse, ovoid to suborbicular, flattened, attached by a long slender funicle; seed-coat thin, crustaceous, light brown; embryo surrounded by a layer of horny orange-colored albumen; cotyledons subfoliaceous, compressed; radicle short, erect, slightly exserted.

Gleditsia is confined to eastern North America, where three species occur, southwestern Asia, China, Formosa, Japan, and west tropical Africa. It produces strong, durable, coarse-grained wood. In Japan the pods are used as a substitute for soap.