Common Name: desert ironwood

Duration: Perennial

Nativity: Native

Lifeform: Tree

General: Slow growing tree 7-10 m tall, with densely canescent, striate, and spiny branches, the spines 5-10 mm long, slightly hooked, black on the tips, with shredding gray bark.

Leaves: Pinnate 3-10 cm long with 4-12 pairs of leaflets, these oblong 5-20 mm long.

Flowers: On axillary racemes 2-6 cm long, with 0.5 mm long deciduous bracts, papilionoid flowers, the calyx narrowly turbinate, densely canescent, the tube 3-4 mm long, with triangular ovate lobes 203 mm long, nearly as wide, the corolla purple, 9-10 mm long, tinged with yellow.

Fruits: Pods 8-9 mm thick, 3-6 cm long, canescent and glandular pubescent, with a broad beak and stipe.

Ecology: Found in desert washes and on low hills often in gravelly to silty soil below 3,000 ft (914 m), flowers April-May.

Distribution: Ranges from Arizona south into southern Sonora and into Baja California.

Notes: Distinctive in spring for its purple flowers, but distinguished from the similar Acaciella greggii by virtue of its much more full crown that is dense gray-green. Well known for its nurse plant qualities and because it is endemic to the Sonoran Desert region.

Ethnobotany: The wood was widely used for fuel, the well known carvings of people like the Seri, and the seeds were roasted, parched and ground for flour and widely used as food. The wood is known for its hardness and was used for all kinds of tools and implements, instruments, carvings, digging sticks, weaving, and even shovels.

Etymology: Olneya is named for Stephan Olney (1812-1878) an American botanist, while tesota is a corruption of the Spanis tieso meaning stiff or firm, referring to the wood of the tree.

Synonyms: None

Editor: SBuckley 2011