Legume compressed or ultimately convex; pinnæ 12—22-foliolate.1. [P. juliflora] (C, E, G, H). Legume thick, spirally twisted; pinnæ 10—16-foliolate.2. [P. pubescens] (E, F, G, H).
1. [Prosopis juliflora] DC. Mesquite. Honey Locust.
Leaves with 2 or rarely 4 pinnæ, and slender terete petioles abruptly enlarged and glandular at base; stipules linear, acute, membranaceous, deciduous. Flowers appearing in successive crops from May to the middle of July, fragrant, about 1/12′ long, on short pedicels, in slender cylindric spikes 1½′—4′ long, on stout peduncles ½′—¾′ in length; calyx glabrous or puberulous, about one fourth as long as the narrowly oblong acute petals, glabrous or puberulous on the outer surface and covered on the inner surface toward the apex with hoary tomentum; stamens twice as long as the corolla, the dark-colored connective of the anther-cells furnished at apex with a stalked gland; ovary short-stalked, clothed with silky hairs. Fruit in drooping clusters, linear, at first flat, becoming subterete at maturity, constricted between the 10-20 seeds, straight or falcate, contracted at the ends, 4′—9′ long, ¼′—½′ wide; seeds about ¼′ long.
A low tree, with a large thick taproot descending frequently to the depth of 40°-50°, and furnished with radiating horizontal roots spreading in all directions and forming a dense mat, a trunk 6′—8′ in diameter, divided a short distance above the ground into many irregularly arranged crooked branches forming a loose straggling head, and slender branchlets at first pale yellow-green, turning darker in their second year, furnished in the axils of the leaves of their first season with short spur-like excrescences covered with chaffy scales, and armed with stout straight terete supra-axillary persistent spines ½′—2′ long, or rarely unarmed; more often a shrub, with numerous stems only a few feet high. Bark of the trunk thick, dark reddish brown, divided by shallow fissures, the surface separating into short thick scales. Wood heavy, close-grained, rich dark brown or sometimes red, with thin clear yellow sapwood; almost indestructible in contact with the soil, and largely used for fence-posts, railway-ties, the underpinnings of buildings, and occasionally in the manufacture of furniture, the fellies of wheels, and the pavements of city streets; the best fuel of the region, and largely made into charcoal. The ripe pods supply Mexicans and Indians with a nutritious food, and are devoured by most herbivorous animals. A gum, resembling gum-arabic, exudes from the stems.
Distribution. Western Texas and eastern New Mexico, and on the island of Jamaica; eastward and westward diverging into two extreme forms. These are
Prosopis juliflora var. glandulosa Cock.
Leaves 8′—10′ long, 2-pinnate, with long slender petioles, the pinnæ 12—20-foliolate; leaflets distant, linear, mostly acute, glabrous, dark green, often 2′ long and ⅛′—¼′ wide. Flowers with a usually glabrous calyx. Fruit occasionally conspicuously constricted between the seeds (f. constricta Sarg.).
A round-topped tree, often 20° high, with a trunk a foot in diameter, and long gracefully drooping branches forming a symmetrical round-topped head.