Leaves 4′—5′ long, with a pubescent rachis grooved on the upper side, 10—23 pairs of leaflets, and small scarious deciduous stipules; leaflets oval, rounded or slightly emarginate at apex, with a stout petiolule and minute scarious deciduous stipels, pale gray-green, glabrous or slightly puberulous on the upper surface, conspicuously glandular, with chestnut-brown glands, and pubescent especially on the prominent midrib on the lower surface, reticulate-veined, ½′—⅔′ long, ⅛′—¼′ wide, with thickened slightly revolute margins. Flowers opening in May, nearly ½′ long, on slender pubescent pedicels, in axillary pubescent spikes 3′—4′ long; calyx many-ribbed, pubescent, conspicuously glandular, half as long as the white petals ciliate on the margins, and of nearly equal size and shape. Fruit ½′ long, pendent, nearly straight or slightly falcate, thickened on the edges, with usually a single seed near the apex; seed compressed, light reddish brown, ¼′ long.
A tree, occasionally 18°—20° high, with a trunk 6′—8′ in diameter, separating 3° or 4° above the ground into a number of slender branches, and branchlets coated when they first appear with ashy gray pubescence disappearing during the second year, and then reddish brown and roughened by numerous glandular excrescences; or more often a low rigid shrub. Bark of the trunk about 1/16′ thick, light gray, and broken into large plate-like scales, exfoliating on the surface into thin layers. Wood heavy, hard, close-grained, light reddish brown, with thin clear yellow sapwood of 7 or 8 layers of annual growth.
Distribution. Dry gravelly soil, on arid slopes and dry ridges; valley of the upper Guadalupe River, western Texas, to the Santa Catalina and Santa Rita Mountains, southern Arizona, and southward into northern Mexico; arborescent in the United States only near the summit of the Santa Catalina Mountains.
14. DALEA L.
Glandular-punctate herbs, small shrubs, or rarely trees. Leaves alternate, unequally pinnate, or simple in the arborescent species; stipules generally minute, subulate, deciduous. Flowers in racemes, their bracts membranaceous or setaceous, broad, concave above, glandular-dentate; calyx 5-toothed or lobed, persistent, the divisions nearly equal; corolla papilionaceous; petals unguiculate; standard cordate, free, inserted in the bottom of the tubular disk connate to the calyx-tube, rather shorter than the wing- and keel-petals, the claws adnate to and jointed upon the staminal tube; stamens 10, sometimes 9 through the suppression of the superior stamen, united into a tube cleft above and cup-shaped toward the base; anthers uniform, often surmounted by a gland; ovary sessile or short-stalked, contracted into a slender subulate style, with a minute terminal stigma; ovules 4—6 attached to the inner angle of the ovary, superposed. Legume ovoid, sometimes conspicuously ribbed, more or less inclosed in the calyx, membranaceous, indehiscent, 1-seeded; seed reniform, without albumen; testa coriaceous; embryo filling the cavity of the seed; cotyledons broad and flat; radicle superior, accumbently reflexed.
Dalea is confined to the New World, where it is distributed from the central, western, and southwestern regions of the United States through Mexico and Central America to Peru, Chile, and the Galapagos Islands; usually herbs or low undershrubs, one species of the United States occasionally assumes the habit and attains the size of a small tree.
The generic name is in honor of Samuel Dale (1659—1739), an English botanist and writer on the materia medica.
1. [Dalea spinosa] A. Gray. Smoke Tree.
Leaves few, simple, irregularly scattered near the base of the spinose branchlets, cuneate or linear-oblong, sessile or nearly sessile, marked by few large glands, especially on the entire wavy margins, hoary-pubescent, ¾′—1′ long, ⅛′—½′ wide, with a broad midrib and three pairs of lateral ribs, on vigorous young shoots or seedling plants remotely and coarsely serrate; remaining only for a few weeks on the branches; stipules minute, ovate, acute, pubescent. Flowers ½′ long, appearing in June on short pedicels from the axils of minute bracts, in racemes 1′—1½′ long, their rachis slender, spinescent, hoary-pubescent; calyx-tube 10-ribbed, with usually 5 glands between the dorsal ribs, the lobes short, ovate, rounded or more or less ciliate on the margins, reflexed at maturity; petals dark violet blue, standard cordate, reflexed, furnished at base of the blade with two conspicuous glands, wing- and keel-petals attached to the staminal tube by their base only and nearly equal in size, rounded at apex, more or less irregularly lobed at base; ovary pubescent, glandular punctate. Fruit ovoid, pubescent, glandular, twice as long as the calyx, tipped with the remnants of the recurved style; seed ⅛′ long, pale brown irregularly marked with dark spots.