Flora of North America species comparison

some-what lax often sprawling, longest stems sometimes prostrate, cylindric, 8–40(–100?) × 3.2–15 cm;

ribs (6–)7–10(–12), crests essentially uninterrupted;

areoles (11–)14–52 mm apart.

erect, spheric, (1–)2–3 × 1–2(–2.5) cm;

ribs 6–9, crests poorly defined, undulate;

areoles of largest plants 6–7(–10) mm apart.

6–14 per areole, straight or central spines slightly curved throughout their lengths, ± opaque, white, pale tan, or purplish gray, often extensively tipped or banded with brown;

radial spines 5–10(–13) per areole, 9.5–40(–47) mm, usually less than 1/2 as long as central spines;

central spines 1–4(–5) per areole, all or mostly projecting, abaxial spine porrect or descending, frequently compressed or angular in cross section (sometimes sulcate, keeled, or striate), (12–)20–84(–96) mm.

8–14(–15) per areole, in relatively old plants curving irregularly in random directions, gray or white, some or all tipped black, dark reddish brown, or dull reddish purple;

radial spines 8–14 per areole, ± pectinately arranged, (5–)10–15(–19) mm;

central spines 0(–1) per areole, terete, 10–12 mm, closely resembling largest radial spines.

(4.5–)5–7.5 × 5–5.6(–9) cm;

flower tube 10–30 × 10–22(–40) mm;

flower tube hairs 1–2 mm;

inner tepals pink or magenta, darkest proximally, 28–55 × 8–14(–20) mm, tips relatively thin and delicate;

anthers yellow;

nectar chamber 4–6 mm.

1.5–2 × 1.5–2(–2.7) cm;

flower tube 5–8 × 5–10 mm;

flower tube hairs very short, inconspicuous;

inner tepals bright yellow-green, often with maroon midstripes, 9–18 × 2.7–3.8 mm, tips relatively thin and delicate;

anthers yellow;

nectar chamber 1 mm.

pale yellow-green or dull reddish, 20–30 mm, pulp white or pale pink.

purplish brown or remaining green when ripe, 5.5–9(–11) mm, pulp white.

= 22.

= 22.