Flora of North America species comparison

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

areoles oval, villous.

depressed-ovoid to ovoid or globose, 2.5–15(–25) × 2.5–15 cm;

areoles circular to oval, villous.

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.

smooth, relatively hard, distinguishable as radial and central;

radial spines 15–35 per areole, widely spreading, white, slender, 3–13 mm;

central spines 4–11 per areole, reddish brown (rarely black) with basal 1/2 cream or yellow, rigid, straight or slightly curved, 5–21 × 0.3 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.

1.2–3 × 1–2.5 cm;

scales and outer tepals minutely toothed and laciniate or entire and often undulate;

outer tepals with greenish brown midstripes, oblong-cuneate, 9–20 × 3–5(–6) mm;

inner tepals white, pink, magenta, yellow, or yellow-green, 12–25 × 4.5–6(–9) mm.

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

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

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

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