whitethorn acacia Fabaceae Vachellia
constricta (Benth.) Seigler & Ebinger
Leaf: Alternate, semi-evergreen, bipinnately compound, 2 to 4 inches long, with 4 to 6 pairs of major leaflets and 8 to 12 pairs of minor, very finely divided leaflets, green to grayish green.
Flower: Species is monoecious; many small, yellow, in a tight round cluster (balls), 1/2 inch across on a 2 to 3 inch long stalk, fragrant, appearing in spring and sporadically throughout the summer.
Fruit: A slender, reddish brown legume (2 to 5 inches long), constricted between seeds, flattened elliptical seeds inside.
Twig: Slender, slightly zigzag, reddish brown, speckled with light colored lenticels, a pair of straight, nearly white spines (1/4 to over 1 inch long) at the base of each leaf, twigs from older plants may entirely lack thorns or have smaller ones; buds sunken in leaf scar.
Bark: Initially smooth and reddish brown to gray-brown, turning brown to gray-brown and becoming furrowed and scaly.
Form: Upright, multi-branched, large, thicket forming shrub or a small tree up to 15 feet in height with a spreading crown.
Looks like: desertfern - catclaw acacia - guajillo - catclaw mimosa