Leaves deciduous, coated when they unfold with hoary pubescence, 6′—9′ long, with a slender puberulous petiole, and 13—19 elliptic, acute or obtuse slightly mucronate leaflets contracted into short stout pubescent petiolules, entire or with slightly wavy thickened margins, thin, pale yellow-green and glabrous above, paler and covered with scattered hairs or nearly glabrous below, 1′—1½′ long and ½′ wide, with a prominent orange-colored midrib, slender primary veins, and conspicuous reticulate veinlets. Flowers ½′ long, appearing in early spring with the young leaves, on slender canescent pedicels nearly ½′ long, from the axils of minute deciduous bracts, in slender pubescent semipendent racemes, 3′—5′ long, from the axils of the leaves at the end of the branches; calyx short-campanulate, abruptly narrowed at base, somewhat enlarged on the upper side, slightly pubescent, especially on the margins of the short nearly triangular teeth; petals short-unguiculate, white tinged with rose color; standard nearly orbicular, slightly emarginate, reflexed, as long and twice as broad as the ovate auriculate wing-petals and the keel-petals; ovary conspicuously stipitate, villose. Fruit ½′—3′ long, indehiscent, black, more or less pubescent, crowned with the thickened remnants of the style, 4—8-seeded, or rarely 1-seeded and then subglobose, with thin fleshy rather sweet walls; persistent on the branches during the winter; seeds oval, slightly compressed, with a thin crustaceous bright chestnut-brown seed-coat; cotyledons surrounded by a thin layer of horny albumen, bright green; radicle long and incurved.
A tree, 18°—20° high, with a trunk 8′—10′ in diameter, dividing into a number of stout spreading branches forming a handsome round-topped head, and slender terete slightly zigzag branchlets, orange-brown or dark brown and slightly puberulous when they first appear, becoming bright green marked by narrow brown ridges, and in their second year by the elevated tomentose leaf-scars. Winter-buds depressed, almost surrounded by the base of the petiole, with broad scales coated on the outer surface with dark brown tomentum and on the inner surface with thicker pale tomentum, and persistent on the base of the growing shoot. Bark of the trunk about ⅛′ thick, dark reddish brown, and broken into numerous oblong scales, the surface exfoliating in thin layers. Wood heavy, very hard and strong, light red in color, with thick bright clear yellow sapwood of 10—12 layers of annual growth.
Distribution. Usually on limestone hills, or on the borders of streams, ravines, or depressions in the prairie, often forming small groves; valley of the Red River at Shreveport, Caddo Parish, Louisiana, to the valley of the Arkansas River, Arkansas, and to southern Oklahoma (Choctaw and Love Counties), and southward in Texas to the valley of the San Antonio and upper Guadalupe Rivers (Kerrville, Kerr County).
12. CLADRASTIS Raf.
A tree, with copious watery juice, smooth gray bark, slender slightly zigzag terete branchlets without a terminal bud, fibrous roots, and naked axillary buds 4 together, superposed, flattened by mutual pressure into an acuminate cone, and inclosed collectively in the hollow base of the petiole, the largest and upper one only developing, the lowest minute and rudimentary. Leaves unequally pinnate, petiolate, with a stout terete petiole abruptly enlarged at base, 7—11-foliolate, deciduous; leaflets usually alternate, broadly oval, the terminal one rhombic-ovate, contracted at apex into a short broad point, cuneate at base, entire, petiolulate, without stipels, covered at first like the young shoots with fine silvery pubescence, and on the midrib with lustrous brown tomentum, at maturity thin, glabrous, dark yellow-green on the upper surface, pale on the lower surface, the midrib and numerous primary veins conspicuous, light yellow below; stipules 0. Flowers on slender puberulous pedicels, bibracteolate near the middle, with scarious caducous bractlets, in long gracefully nodding stalked terminal panicles, the lower branches racemose, and often springing from the axils of 1-flowered pedicels, the main axis slightly zigzag, and, like the branches, covered at first with a glaucous bloom and slightly pilose; bracts lanceolate, scarious, pale, caducous; calyx cylindric-campanulate, enlarged on the upper side, and obliquely obconic at base, puberulous, 5-toothed, the teeth imbricated in the bud, nearly equal, short and obtuse, the 2 upper slightly united; disk cupuliform, adnate to the interior of the calyx-tube; corolla papilionaceous; petals white, unguiculate; standard nearly orbicular, entire or slightly emarginate, reflexed above the middle, barely longer than the straight oblong wing-petals, slightly biauriculate at the base of the blade, marked on the inner surface with a pale yellow blotch; keel-petals free, oblong, nearly straight, obtuse, slightly subcordate or biauriculate at base; stamens 10, free; filaments filiform, slightly incurved near the apex, glabrous; anthers versatile; ovary linear, stipitate, bright red, villose with long pale hairs, contracted into a long slender glabrous slightly incurved subulate style; stigma terminal, minute; ovules numerous, suspended from the inner angle of the ovary, superposed. Legume glabrous, short-stalked, linear-compressed, the upper margin slightly thickened, tipped with the remnants of the persistent style, 4—6-seeded, ultimately dehiscent, the valves thin and membranaceous. Seeds short-oblong, compressed, attached by a slender funicle; without albumen; seed-coat thin, membranaceous, dark brown; embryo filling the cavity of the seed; cotyledons fleshy, oblong, flat; radicle short, inflexed.
Four species are now known. One inhabits the southern United States, two occur in western China and one in Japan.
Cladrastis, from κλάδος and θραυστός, relates to the brittleness of the branches.
1. [Cladrastis lutea] K. Koch. Yellow Wood. Virgilia.
Leaves 8′-12′ in length, with leaflets 3′—4′ long and 1½′—2′ wide, the terminal leaflet rather shorter than the others and 3′—3½′ wide; turning bright clear yellow rather late in the autumn some time before falling. Flowers appearing about the middle of June, slightly fragrant, in panicles 12′—14′ long and 5′—6′ wide. Fruit fully grown by the middle of August, ripening in September and soon falling.