Koeberlinia spinosa var. tenuispina
Plants 1–10 m; young thorns densely puberulent; mature thorns 33–82 mm, 1.2–2 mm at base (20+ times longer than base width). Flowers: petals 4–4.8 mm; style 1–1.2 mm, straight (sometimes uncinate or S-shaped when dry); gynophore (stipe) 0.5–0.8 mm.
Phenology: Flowering Mar–Jul.
Habitat: Desert areas
Elevation: 0-900 m
Ariz., Calif., Mexico (Baja California, Baja California Sur, Sonora).
Variety tenuispina is a component of the Sonoran Desert flora, occurring in La Paz and Yuma counties in southwest Arizona, Imperial County in southeastern California, and adjacent northwest Mexico.