Flora of North America species comparison

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

areoles oval, villous.

globular to short cylindric, 0.7–5.5 × 1–3 cm;

areoles circular, 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, all radial, mostly 18–26 per areole, spreading, recurved, or somewhat pectinate, reddish tan, pink, or white, 1–1.5 mm, canescent.

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.

1–3.5 × 1–2.5 cm;

scales and outer tepals essentially entire, often undulate;

outer tepals with brownish midstripes to 1.5 mm wide, 4–17 × 4–6 mm;

inner tepals pink, oblanceolate, 8–25 × 3–8 mm.

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

green, drying reddish tan, turbinate,4 × 3 mm.

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

black, 1.5 × 1–1.2 mm, papillate but not rugose.