Flora of North America species comparison

upper portion of primary root somewhat thickened and succulent proximally, otherwise fibrous.

flat-topped or spheric, 4–8 × 4–8 cm, ± flaccid;

tubercles 6–24 mm;

axils appearing naked;

cortex and pith mucilaginous;

latex absent.

tubercles 6–21 mm.

9–31(–34) per areole, white, usually tipped brown;

radial spines 8–30 per areole, in 1 series, glabrous (puberulent in first year flowering plants);

lateral spines bristlelike, 7–11 mm, stiff, longest and thickest of spines;

adaxial spines often darker;

central spines 1–4(–7) per areole, porrect or strongly projecting, 1 or all hooked, (5–)12–14(–21) mm;

subcentral spines 0.

2.5–3.5(–5.2) × 2.2–4.5(–7.5) cm;

outer tepal margins conspicuously fringed;

inner tepals rose-pink or magenta [white], margins often paler;

stigma lobes yellow or pale green (rarely reddish).

2.2–5.1 cm diam.

green or dull purple, spheric to ovoid or obovoid, (9–)13–20(–28) × (6–)7–1.9(–26) mm, juicy throughout;

floral remnant persistent.

6–15 mm diam.

black, 1.3–1.5 mm, pitted;

testa hard, anticlinal cell walls straight (not undulate);

interstices conspicuously narrower than pit diameters;

pits bowl-shaped.

spines usually 16–30 per areole.

= 22.