Plants 0.5-10 m, spreading, globose, compact to somewhat open. Stems ± terete, green twigs thorn-tipped, 25-70 cm. Leaves 0.2-1.5 × 0.5 mm. Inflorescences 3-15 mm. Pedicels 3-6 mm. Flowers: sepals greenish white, ovate-deltate, 1-2 mm, glabrous; petals greenish white or cream, obovate or oblanceolate, 3-4.8 × 0.8-1.4 mm; filaments brownish, 2.8-4 mm, flat; anthers 0.8-1 mm, slightly curved; gynophore (stipe) 0.3-0.8 mm; ovary ovoid, 1-1.2 mm; style 0.4-1.4 mm. Fruits ca. 5 mm, mucronate from persistent style. Seeds 3-3.5 mm. 2n = 44, 88.

Common Name: crown of thorns

Duration: Perennial

Nativity: Native

Lifeform: Tree

General: Shrubs to trees to 5 m tall, with spine-tipped, interlacing branches and twigs, bark gray-green on mature branches, young branches yellow-green and sometimes pubescent.

Leaves: Linear-subulate, 1.5-2 mm long.

Flowers: Inflorescence a small rounded raceme 1-6 cm long, the rachis spine- tipped, with slender pedicels 4-6 mm long, the sepals broadly ovate 1-1.5 mm long, the petals 4-4.5 mm long, rounded at apex, pale yellow, with 8 stamens equaling petals.

Fruits: Globose red to black berries up to 4-5 mm in diameter.

Ecology: Found on old alluvium, gravelly, or sandy substrates on slopes or Larrea flats from 2,000-5,000 ft (610-1524 m); flowers in April-July.

Distribution: s CA, s AZ, s NM, TX; south to c MEX.

Notes: K. spinosa is distinctive with its ruthless, stiff green branches ending in spines; mostly leafless stems and berries. It may form loose thickets, especially on north-facing slopes when occurring near the Arizona-Sonoran border.

Ethnobotany: Unknown

Etymology: Koeberlinia is named after Christoph Ludwig Koeberlin (1794-1862), a German clergyman and botanist, while spinosa is from Latin for thorny.

Synonyms: None

Editor: LCrumbacher 2011, FSCoburn 2015