Common Name: whitethorn acacia

Duration: Perennial

Nativity: Native

Lifeform: Tree

General: Spreading shrubs to 3 m, symmetrical with generally straight branches. Bark smooth, light gray to mahogany-colored, lower branches spreading near ground level. Stipular spines in pairs at the nodes of the stems, usually white, 1-3 cm.

Leaves: Winter deciduous and tardily drought deciduous, even-pinnate, 3.5-4 cm long, the pinnae 3-9 pairs, leaflets many 1.5-3 mm. Petioles with a prominent nectary gland.

Flowers: Fragrant, bright yellow in rounded heads about 1 cm in diameter.

Fruits: Pods 4.5-13.5 cm long by 4-6 mm width, constricted between each seed, moderately compressed, reddish with viscid glands, gradually dehiscent.

Ecology: Found along washes, on slopes and mesas from 2,000-6,500 ft (610-1981 m); flowers April-June.

Distribution: AZ, s NM, TX, VA; south to n MEX.

Notes: Formerly in the genus Acacia, distinguished by its straight white spines; relatively small leaflets, 3 mm or less long; and narrow seed pods with constrictions between the seeds. Similar to Acacia neovernicosa but often larger, to 3 m tall and becoming tree-like; has 3- pairs of pinnae (1-2 pairs, occasionally 3 in A. neovernicosa) and is less sticky-viscous than A. neovernicosa. It differs from A. greggii and Mimosa biuncifera by having straight spines (curved in the others) and Calliandra eriophylla is unarmed. Acacia farnesiana has larger leaflets 2-6 mm long and wider woody seed pods without constrictions between the seeds. Note the nomenclature change for the entire genus.

Ethnobotany: Seri made a tea from the mashed seeds and leaves to relieve diarrhea or upset stomachs. Powdered, dried pods and leaves have been used to treat skin rashes, medicinal tea can be made from the roots.

Etymology: Acacia is from Greek akakie taken from ake or akis, -a sharp point, while constricta refers to constricted or contracted.

Synonyms: Acacia constricta

Editor: SBuckley 2010, FSCoburn 2015

Plant: Shrub to 4 m, usually with paired spines at nodes aging white

Leaves: leaves alternate, twice compound with 3-5 pinnae

Flowers: flowers yellow, in dense globose heads

Fruit: a linear strait-slightly curved pod, strongly constricted between seeds. Note: #1556 large specimen collected 5 miles north of Hunter Wash with minute spines, sometimes referred to as var. paucispinus.

References: Kearney & Peebles; Arizona Flora. McDougall; Seed plants of Northern Arizona. ASU specimans