Contr. U.S. Natl. Herb. 12: 435. 1909.
Shrubs, ascending to erect, spreading, or reclining, usually much branched near base, forming thickets. Roots diffuse. Stems somewhat segmented, green, long cylindric, 30–150 × 3–5 (–6) cm, glabrous; ribs (12–) 14–18, rounded; tubercles low, indistinct; areoles to 10 mm apart on rib crests, circular, felty; areolar glands absent; cortex and pith mucilaginous. Spines 30–45 per areole, straw colored, aging brown, acicular, terete; radial spines 613 mm; central spines 1–3 per areole, to 60 mm, longest spines bend downward. Flowers diurnal, lateral to terminal on stems, from adaxial edge of areole, never on first-year shoots, funnelform, 3.5–5 cm; flower tube 15–20 mm; tepals 12–20 mm; outer tepals yellow with green or reddish midstripes and tips, oblanceolate; inner tepals yellow, oblanceolate to oblong; ovary subglobose, spines usually absent; scales deltate to ovate or awl-shaped, 1–4 mm, margins entire, with tannish hairs in axils, spiny or spineless; stigma lobes 911, pale-yellow, 4–5 mm. Fruits dehiscent by extruding ribbon of pulp with seeds through apical pore, green with reddish tubercles, spheric, 25–30 mm, juicy, becoming dry after dehiscence, densely spiny like stems; pulp red; floral remnant persistent. Seeds black, obovoid, 2–3 mm, glossy; testa cells ± flat to slightly concave. x = 11.
sw United States, nw Mexico