Plant: shrub or small tree; 2-5(-10) m tall; branches straight, slender, ascending

Leaves: represented merely by a few alternate, widely spaced, soon deciduous, deltoid scales 1-2 mm long; stipules apparently absent; obtuse apically

INFLORESCENCE: cymes short, few-flowered, axillary, often several arising together from a single leaf axil; bracts numerous, minute, deltoid

Flowers: perfect; sepals 1 mm long and wide, acute, firm, tending to persist after anthesis; calyx lobes 5, imbricate in bud, brown, deltoid, small; petals 5, distinct, imbricate in bud, oblong to narrowly obovate, greenish white to yellowish white, 3.5-4 mm long, longer than the calyx lobes; stamens 5, tending to persist at base of fruit, slightly shorter than the petals, the anthers obcordate; pistil of (3-)5 carpels on a short, thick gynophore, the style slender, columnar, long 2-3 mm long, with 5 erect, deltoid, adaxially stigmatic apical lobes, ca. 0.2 mm

Fruit: capsules 15-33 mm long at maturity, the seed-bearing portion ellipsoidal. SEEDS 7-8 mm long, minutely papillose, winged, the body 3-3.5 mm long, the wing membranaceous, as wide as body and about as long

Misc: Sonoran Desert, desert grassland, juniper, and chaparral communities, often calcareous (and perhaps gypsiferous) slopes, sometimes locally dominant; (350-)600-1600 m [(1100-)2000-5200 ft]; (Mar-)May-Aug(-Sep)

REFERENCES: Brasher, Jeffrey W. 1998. Celastraceae J. Ariz. - Nev. Acad. Sci. 30(2): 57.

Common Name: crucifixion thorn

Duration: Perennial

Nativity: Native

Lifeform: Tree

General: Shrub, 2-5 m tall with slender, rigid, spine-tipped branches which are flexible when young; branchlets pale green.

Leaves: Small, scale-like and soon deciduous; triangular-ovate, obtuse at apex, about 1-1.5 mm long, leaving minutely papillose elevations as scars.

Flowers: On racemes 1-3 cm long along branches, the parts glabrous; pedicels 2-6 mm long, calyx lobes deltoid, 1 mm long, subfleshy, margins finely erose; petals 3.5-4 mm long, oblong to narrowly oblanceolate, white; stamens equaling petals.

Fruits: Dehiscent capsule along 10 lines, ovoid-elliptic, dark brown, faintly glaucous, body 6-8 mm in diameter, 9-13 mm long, awl shaped beak, 5-10 mm long; seed 3-3.5 mm long, dark brown with thin wing, as wide as body and as long.

Ecology: Found on arid slopes from 2,000-5,000 ft (610-1524 m); flowers May-August.

Distribution: s UT, AZ, se CA, nw MEX

Notes: Told apart from the similar looking Koeberlinia by the fruit being a 2-celled berry and not having winged seeds; Koeberlinia is in the Caper (Capparaceae) family, so it has four sepals and petals. Koeberlinia is also found largely in the Chihuahuan desert, so it does not spread much past the Gila River. In the middle elevations just above the Parkinsonia communities in the Sonoran Desert, this becomes a more dominant plant. Can also be confused with Parkinsonia because of its green stems. Look for the growth form with many mostly parallel branches reaching for the sky or curving over; and the dark brown trunks (palo verde trees have green trunks and branches that spread at sharper angles).

Ethnobotany: The berries are edible and were eaten.

Etymology: Uncertain origins

Synonyms: None

Editor: SBuckley, 2010