Plant: Shrub, tree < 10 m; crown generally ± narrow; stem: branches ascending; spines 4-12 mm; roots long, spreading Leaves: even-2-pinnate, alternate, deciduous, hairy; primary leaflets 1 or 2 pairs, 3-5 cm, opposite; secondary leaflets 5-8 pairs, 2-10 mm, opposite, oblong, length 2-3 X width INFLORESCENCE: raceme, 4-8 cm, spike-like, many-flowered Flowers: radial, small, greenish white or yellow; calyx shallowly bell-shaped, lobes very short; petals generally inconspicuous, fused, 2-3 mm; stamens 10, exserted, free; style exserted, generally appearing before stamens Fruit: legume, 3-5 cm, tightly coiled, indehiscent, ± flat, pulpy when young, then woody; Seeds several, generally 3 mm, ovoid Misc: Creek, river bottoms, sandy or gravelly washes or ravines; 100-1300 m.; Apr-Sep Notes: spines are white and slender, fruits are spirally coiled. References: Kearney & Peebles; Arizona Flora. McDougall; Seed plants of Northern Arizona. ASU specimans