Flora of North America species comparison

erect, ovoid, becoming cylindric with age, 11–23(–40) × (4.5–)5.5–7(–10) cm;

ribs (13–)15–19(–21), crests rather sharply undulate;

areoles 5–11 mm apart.

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.

19–28 per areole, straight, appressed (radial spines) or spreading in all directions (central spines), presenting relatively bristly appearance (except when spines very short, and then having relatively smooth appearance as in E. pectinatus), pink to pale yellow, white, or tan, less often dark brown or purplish, annual growth increments marked (often vaguely) by rings of spines with contrasting colors;

radial spines (16–)17–25(–28) per areole, 5–15(–25) mm;

central spines (2–)8–12(–15) per areole, terete, largest spines 4.5–9.5(–14) mm.

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.

7–8.5(–10) × 7–12 cm;

flower tube 10–20 × to 10 mm;

flower tube hairs 1–3 mm;

inner tepals either yellow (rarely orange-yellow, sometimes becoming salmon- or rose-pink with age), or rose-pink to magenta, proximal 5–30% green in either case, (25–)32–69(–77) × 8–23 mm, tips relatively thin and delicate;

anthers yellow;

nectar chamber 2–6 mm.

(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.

dark dull purplish to maroon (sometimes remaining green), 2–3.5 cm, pulp white to purplish pink.

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

= 44.

= 22.