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.