Flora of North America species comparison

depressed-ovoid to elongate-ovoid, 5–30 × 5–15 cm;

areoles oval, villous.

gray-green, obovoid, globose or depressed-globose, 2–6.5 × 1.5–5.5 cm;

areoles circular, lanulose.

smooth, hard and rigid, distinguishable as radial and central;

radial spines 10–30 per areole, spreading at right angles to tubercles, nearly straight, white to dull reddish brown, 8–20 mm;

central spines 6–12 per areole, widely spreading or nearly erect, reddish brown to nearly black, rigid, straight or slightly curved, base yellow or cream, 15–35 mm, less than 1 mm diam. at base.

soft and corky or spongy, harder at tips, white to pale gray, all radial or with 1 central and sometimes 0–1 intermediate spines per areole;

radial spines 3–7 per areole, 2–9 × 0.5–1 mm; intermediate spines curved upward, 8–21 × 0.7–1.5 mm;

central spine, when present, 5–18 × 1 mm.

1–3.5 × 2.5–5 cm;

scales and outer tepals of flower tube minutely toothed, laciniate, or entire and undulate;

outer tepals with greenish brown midstripes, oblong-cuneate, 12–25 × 4.5–9 mm;

inner tepals white, pink, magenta, yellow, or yellow-green, 19–27 × 5–10 mm.

1–1.4 × 1.5–2.5 cm;

scales and outer tepals minutely toothed or denticulate or entire and undulate;

outer tepals with brown-purple midstripes, oblanceolate, 5–13 × 2–4.5 mm;

inner tepals cream, yellow, or yellowish green, lanceolate, 6–12(–15) mm.

green tinged with red, drying reddish brown, short cylindric, 6–11 × 5–10 mm.

green, drying reddish brown, turbinate, 6–11 × 5–8 mm.

gray to black, 2–3 × 1.5–2 mm, papillate but not rugose.

dark brown to black, 3 × 2 mm, papillate and rugose.