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.
The generic name is in honor of Johann Gottlieb Gleditsch (1714—1786), professor of botany at Berlin.
CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES.
Legume linear-oblong, elongated, many-seeded, indehiscent. Legume 12′—18′ long, with pulp between the seeds; ovary hoary-tomentose.1. [G. triacanthos] (A, C). Legume 4′—5′ long, without pulp between the seeds.2. [G. texana] (C). Legume oval, oblique, 1—3-seeded, without pulp, tardily dehiscent; ovary glabrous.3. [G. aquatica] (A, C).
1. [Gleditsia triacanthos] L. Honey Locust.
Leaves 7′—8′ long, 18—28-foliolulate or sometimes bipinnate, with 4—7 pairs of pinnæ, those of the upper pair 4′—5′ long, when they unfold hoary-tomentose, and at maturity pubescent on the petiole and rachis, the short stout petiolules, and the under surface of the midrib of the oblong-lanceolate leaflets, unequal at base, acute or slightly rounded at apex, remotely crenulate-serrate, dark green and lustrous above, dull yellow-green below, 1′—1½′ long and ½′ wide; turning in the autumn pale clear yellow. Flowers appearing in June when the leaves are nearly fully grown from the axils of leaves of previous years; the staminate in short many-flowered pubescent racemes 2′—2½′ long and often clustered; the pistillate in slender graceful few-flowered usually solitary racemes 2½′—3½′ long; calyx campanulate, narrowed at base, the acute lobes thickened, revolute and ciliate on the margins, villose with pale hairs, rather shorter than and half as wide as the erect acute petals; filaments pilose toward the base; anthers green; pistil rarely of 2 carpels, hoary-tomentose. Fruit 12′—18′ long, dark brown, pilose and slightly falcate, with straight thickened margins, 2 or 3 together in short racemes on stalks 1′—1½′ long, their walls thin and tough, contracting in drying by a number of corkscrew twists, and falling late in the autumn or early in winter; seeds oval, ⅓′ long, separated by thick succulent pulp.
A tree, 75°—140° high, with a trunk 2°—3° or occasionally 5°—6° in diameter, slender spreading somewhat pendulous branches forming a broad open rather flat-topped head, and branchlets marked by minute lenticels, at first light reddish brown and slightly puberulous, soon becoming lustrous and red tinged with green, and in their second year greenish brown and armed with stout rigid long-pointed simple or 3-forked spines at first red, and bright chestnut-brown when fully grown, or rarely unarmed (var. inermis Pursh.). Bark of the trunk ½′—¾′ thick, divided by deep fissures into long narrow longitudinal ridges and roughened on the surface by small persistent scales. Wood hard, strong, coarse-grained, very durable in contact with the ground, red or bright red-brown, with thin pale sapwood of 10—12 layers of annual growth; largely used for fence-posts and rails, for the hubs of wheels, and in construction.
Distribution. Borders of streams and intervale lands, in moist fertile soil, usually growing singly or occasionally covering almost exclusively considerable areas; less commonly on dry sterile gravelly hills; western slope of the Alleghany Mountains of Pennsylvania, westward through southern Ontario and southern Michigan to southeastern Minnesota, southern Iowa, southeastern South Dakota, eastern Nebraska, eastern Kansas, and Oklahoma to the Salt Fork of the Arkansas River (near Alva, Woods County) and to creek valleys near Cache, Comanche County (G. W. Stevens), and southward to northern Alabama, Mississippi and western Florida and to the valley of the Brazos River, eastern Texas; and in the cañon of Paloduro Creek near Canyon, Randall County, northwestern Texas (E. J. Palmer); in Pennsylvania and West Virginia occasionally on the eastern slopes of the Appalachian Mountains; attaining its largest size in the valleys of small streams in southern Indiana and Illinois; now often naturalized in the region east of the Alleghany Mountains. The var. inermis, the prevailing form in Taney County, southern Missouri.
Often cultivated as an ornamental and shade tree in all countries of temperate climates.
2. [Gleditsia texana] Sarg. Locust.
Leaves 6′—7′ long, 12—22-foliolulate, with a slender rachis at first puberulous, ultimately glabrous, or often bipinnate, usually with 6 or 7 pairs of pinnæ, the lower pairs frequently reduced to single large leaflets; leaflets oblong-ovate, often somewhat falcate, rounded or acute or apiculate at apex, obliquely rounded at base, finely crenately serrate, thick and firm in texture, dark green and lustrous above, pale below, ½′—1′ long, with a short petiolule coated while young, like the base of the slender orange-colored midrib, with soft pale hairs. Flowers appearing toward the end of April, the staminate dark orange-yellow, in slender glabrous often clustered racemes lengthening after the flowers begin to open and finally 3′—4′ in length; calyx campanulate, with acute lobes thickened on the margins, villose-pubescent and rather shorter and narrower than the puberulous petals; stamens with slender filaments villose near the base and green anthers; pistillate flowers unknown. Fruit 4′—5′ long, 1′ wide, straight, much compressed, rounded and short-pointed at apex, full and rounded at the broad base, thin-walled, dark chestnut-brown, puberulous, slightly thickened on the margins, many-seeded, without pulp; seeds oval, compressed, dark chestnut-brown, very lustrous, ½′ long.
A tree, 100°—120° high, with a trunk rarely exceeding 2½° in diameter, ascending and spreading branches forming a narrow head, and comparatively slender more or less zigzag branchlets roughened by numerous small round lenticels, light orange-brown when they first appear, gray or orange-brown during their first year, ashy gray the following season, and unarmed. Bark thin and smooth.
Distribution. Only in a single grove on the bottom-lands of the Brazos River, near the town of Brazoria, Brazoria County, Texas.
3. [Gleditsia aquatica] Marsh. Water Locust.
Leaves 5′—8′ long, 12—20-foliolate, or bipinnate, with 3 or 4 pairs of pinnæ; leaflets ovate-oblong, usually rounded or rarely emarginate at apex, unequally cuneate at base, slightly and remotely crenate or often entire below the middle, glabrous with the exception of a few hairs on the short stout petiolule, dull yellow-green and lustrous on the upper surface, dark green on the lower surface, about 1′ long and ⅓′—½′ wide. Flowers appearing in May and June after the leaves are fully grown on short stout purple puberulous pedicels, in slender racemes 3′—4′ long; calyx-tube covered with orange-brown pubescence, the lobes narrow, acute, slightly pilose on the two surfaces, as long as but narrower than the green erect petals rounded at apex; filaments hairy toward the base; anthers large, green; ovary long-stipitate, glabrous. Fruit fully grown in August, pendent in graceful racemes, obliquely ovoid, long-stalked, crowned with a short stout tip, thin, 1′—2′ long, 1′ broad, without pulp, its valves thin, tough, papery, bright chestnut-brown, lustrous and somewhat thickened on the margins; seeds 1 or rarely 2 or 3, flat, nearly orbicular, orange-brown, ½′ in diameter.
A tree, 50°—60° high, with a short trunk 2°—2½° in diameter, usually dividing a few feet from the ground into stout spreading often contorted branches forming a wide irregular flat-topped head, and glabrous orange-brown branchlets becoming in their second year gray or reddish brown, marked by occasional large pale lenticels, and armed with usually flattened simple or short-branched straight or falcate sharp rigid spines 3′—5′ long, about ½′ broad at the base, and dark red-brown and lustrous. Bark ⅛′—¼′ thick, smooth, dull gray or reddish brown, and divided by shallow fissures into small plate-like scales. Wood heavy, very hard and strong, coarse-grained, rich bright brown tinged with red, with thick light clear yellow sapwood of about 40 layers of annual growth.
Distribution. Eastern South Carolina to Florida, through the coast region of the Gulf states to the valley of the Brazos River, Texas, and northward through western Louisiana and southern Arkansas to northwestern Mississippi, middle Kentucky and Tennessee, the bottoms of the Mississippi at La Pointe, Saint Charles County, Missouri, western and southern Illinois and southwestern Indiana; rare east of the Mississippi River and only in deep river swamps; very abundant and of its largest size westward on rich bottom-lands; in Louisiana and Arkansas often occupying extensive tracts submerged during a considerable part of the year.