Flora of North America species comparison

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

areoles oval, villous.

subglobose to obovoid, 3.2–6.2 × 2.5–5 cm;

areoles elliptic, 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.

smooth, relatively hard, spreading to recurved, somewhat pectinate, usually all radial (rarely with central spines);

radial spines (7–)13–16(–18) per areole, tips bending downward, yellowish tan or white, 3–5 × 0.7 mm;

central spines 0(–2) per areole, dark tan, rigid, straight or slightly curved, 3–4 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 × 1.5–3 cm;

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

outer tepals straw yellow with green or red-brown midstripes, 3–15 × 3–4.5 mm;

inner tepals straw colored, 9–15 × 3–4.5 mm.

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

green turning reddish brown, turbinate, 7–10 × 10 mm.

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

brownish black, to 2.7 × 1.7–2 mm, papillate and rugose.