Leaves 6′—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. Flowers on 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. Fruit 6′-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; seeds conspicuously 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. Bark about ⅜′ thick, dark brown, divided into low ridges and broken on the surface into small closely appressed persistent scales. Wood heavy, 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.
2. [Leucæna retusa] Benth.
Leaves 3′ 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. Flowers short-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. Fruit solitary 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; seeds ⅓′ 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).
3. [Leucæna pulverulenta] Benth. Mimosa.
