Prosopis glandulosa Torrey var. glandulosa, honey mesquite. Small tree or shrub, winter–deciduous, spinescent, deep–rooted, 1—several–stemmed at base, in range to 6 m tall; shoots with only compound cauline leaves, leaves mostly drooping to pendent on flexible petioles, appearing glabrous but immature parts sparsely puberulent with short–lived hairs; spine solitary (never in pairs), = determinate short shoot and stem spine, formed on vigorous long shoot from axillary bud, stem spine formed without leaves, to 40 mm long, aging woody and sharp–tipped.
Stems cylindric, zigzagged.
Leaves helically alternate, even 2–pinnately compound with 1 pair of primary leaflets to 140 mm long with 8—10 pairs of leaflet blades spaced to 10 mm apart, petiolate with pulvinus, with stipules; stipules 2, attached to leaf base below pulvinus, acuminate, 2.5—3 mm long; petiole pulvinus, to 3 mm long, above pulvinus channeled, to 50 mm long, flexible, lacking hairs at maturity, at top between primary leaflets with extrafloral nectary on upper side, 1 mm diameter, green, flat–topped later depressed; extension beyond primary leaflets on lower side, acuminate, 2—4 mm long; petiolule of primary leaflet to 20 mm long, pulvinus, ca. 3 mm long, green and often wrinkled, rachis narrowly channeled and somewhat 4–sided; rachis 3–sided with central ridge on upperside, to 80 mm long, above and below secondary petiolule with orangish, papillate patches; stipel subtending secondary petiolule on lower side, to 0.25 mm long, early–abscised; secondary petiolule = pulvinus, 1.5 mm long, green, soon glabrous, at base, at base with minute food bodies; blades of secondary leaflets widely spreading, linear–oblong to linear–elliptic, (< 15—) 25—40 × 3—4.5(—10.5) mm, slightly oblique at base, entire, acute at tip, 1–veined at base with midrib somewhat raised on both surfaces, venation asymmetric with midrib closer to leading edge, when immature puberulent–ciliate on margins.
Inflorescence raceme, several racemes clustered arising from axillary, unexpanded short shoot along twigs, raceme 100+–flowered, cylindric, mostly 65—70 × 13—14 mm, flowered alternate, not evenly spaced, tightly packed and radiating from rachis, opening at the same time, bracteate, essentially glabrous; bract at base of peduncle 3–parted including 2 stipules and diminutive blade on fleshy base, stipules acute–triangular, to 1.5 mm long, short–ciliate on margins; peduncle short with flowers nearly to base; rachis cylindric, glabrous; bractlet subtending pedicel awl–shaped and cupped, 0.5—1 mm long, membranous with green midvein, with raised base subtending pedicel, short–ciliate on margins, having minute food bodies at base, early–deciduous; pedicel cylindric, 1—1.3 mm long, ≥ bractlet, with short pulvinus at base, light green.
Flower bisexual, radial, ca. 5 mm across (stamens); proterogynous with stigma exserted in bud; receptacle with nectary disc surrounding stalk of ovary and inside bases of stamens, nectary disc 5–lobed, 0.2 mm long, calyx 5–lobed, ± 1.5 mm long; tube bell–shaped, colorless with 5 yellow–green veins to lobes; lobes triangular, ca. 0.4 mm long, short–ciliate on margins; petals 5, ascending to suberect, oblanceolate, ± 3 × 0.9—1 mm, colorless to midpoint with 1 yellow–green vein, greenish above midpoint, upper surface white–tomentose above midpoint, lower surface in bud with some short hairs approaching tip; stamens 10, free, ascending; filaments cylindric, 5.5—6 mm long, green in bud aging cream–colored; anthers dorsifixed, dithecal–versatile, 0.7—0.8 mm long, cream–colored and aging reddish between sacs, longitudinally dehiscent, in bud anther at top having a short–stalked food body, subspheroid, 0.15—0.2 mm, whitish and minutely bumpy, abscised before anthesis; pollen yellowish; pistil 1, ca. 6 mm long, stalked (stipe), stalk cylindric, < 1 mm long, cream–colored, glabrous; ovary superior, cylindric, 1 mm long, green, densely white–villous, 1–chambered with 15+ ovules attached to upper side; style exserted ca. 3.5 mm, curved, white aging cream–colored, with short hairs to midpoint; stigma terminal, recessed ca.0.25 mm.
Fruit pod (legume), stalked (stipe) with stalk to 8 mm long, indehiscent, 9—15–seeded, broadly linear straight to slightly curved, mostly bulging at seeds or slightly constricted on edges, mostly 100—160 × ca. 8 × 4 mm including beak (style), when dry yellowish brown, solid (lacking air chambers) with seeds embedded in sweet pulp, sides somewhat glossy with wavy, lengthwise veins and minute whitish specks.
Seed oblong–ellipsoid to somewhat ovoid, 6—7 × 5—6 mm, light brown, with hard seed coat.
A. C. Gibson