Flora of North America species comparison

fleshy taproots, to 24 cm, 5–8 cm diam.

short, obconic taproots;

secondary roots diffuse.

cylindric to ovoid-cylindric, commonly 5–15(–25) × 3.5–7(–10) cm, flaccid;

tubercles 4 mm diam.;

axils short woolly;

cortex and pith mucilaginous;

latex absent.

flat-topped (in old age or under dense brush aerial portion of stem hemispheric), 10 × 8–10(–30) cm, firm;

tubercles 8–17 × 4–11 mm;

axils bearing (at least seasonally) woolly tufts, wool 3–5 mm, bristles absent;

cortex and pith not mucilaginous;

latex abundant in healthy tissue throughout cortex of stem, tubercles, and sometimes flower receptacle, sticky, white.

21–64 per areole, dark or light colored, depending largely on substrate color, glabrous (to hoary);

radial spines 30–46(–60) per areole, white, bristlelike, 6–10 × 0.09–0.15 mm, stiff;

central spines 1–3(–4) per areole, porrect or strongly projecting, usually hooked, (6–)13–18(–25) × (0.2–)0.3(–0.4) mm;

subcentral spines several, often 12+ per areole, radiating in all directions, often resembling supplementary ring of radial spines, barely distinguishable from radial spines, stouter, longer and dark tipped or purplish.

(6–)7–8(–10) per areole, white, reddish brown, gray, or yellowish, glabrous;

radial spines (5–)6–7(–9) per areole, largest spines reddish brown, gray, or yellowish, tips blackish or dark brown, needlelike, 6.5–13.5 × 0.3–0.6 mm, stiff;

central spines (0–)1 per areole, usually ascending and inconspicuous against radial spines, sometimes porrect, straight or slightly curved, largest spines (3–)5–12 × 0.3–0.7 mm;

subcentral spines 0.

2.5 × 2.5–3.5 cm;

outermost tepal margins long fringed;

inner tepals pink to rose-purple, margins sometimes paler or white, at least proximally, 24–26 × 4 mm;

stigma lobes yellow-green to green.

2.5–3.5 × 1.9–3.5(–4.4) cm;

outermost tepal margins entire;

inner tepals white to pale pink, often with pink or lavender midstripes, 8–15 mm;

stigma lobes light green, 3–5 mm.

bright red, ellipsoid or cylindric to clavate, (8–)15–30 × 5–10 mm, juicy only in fruit walls;

floral remnant quickly deciduous, leaving conspicuous abscission scar.

purplish pink, clavate to obovoid, 20–32 mm, juicy only in fruit walls;

floral remnant weakly persistent.

black, conspicuously strophiolate, 1.4–2.4 × 1.4 mm, pitted and rugose;

testa hard;

anticlinal cell walls straight (not undulate);

interstices narrower than pit diameters;

pits bowl-shaped;

strophiole tan, large, corky.

reddish brown, 1.1–1.2 mm;

pitted;

testa leathery to hard, anticlinal cell walls strongly undulate, interstices much narrower than pit diam., pits deeply concave, elongate.

= 22.

= 22.