Flora of North America species comparison

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

areoles oval, villous.

subglobose to globose, 3–7.5 × 2.5–5.5(–8) 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, thin and flexible, sometimes distinguishable as radial and central;

radial spines 13–22 per areole, straight or curving irregularly, white, 20–25 × 0.2–0.3 mm;

central spines 3–6 per areole, dense in mature plants, white to pale gray, straight, flexible, hairlike, 8–35 × 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.

1.5–2.2 × 1.9–2.5 cm;

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

outer tepals brown midstripes with pale or white margins, oblanceolate, 8–20 × 3–6 mm;

inner tepals light yellow to pink, oblanceolate, 15–20 × 4–6 mm.

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

greenish yellow maturing to reddish brown, cylindric, 7–10 × 5–8 mm.

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

black, 2.5 × 2 mm, papillate but not rugose.