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.