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.

usually flat-topped (in old age or under dense brush hemispheric), 4–20 × 9-25(–30) cm, firm;

tubercles 10–17 × 6–8.5 mm;

axils woolly, wool 5–8 mm, bristles absent;

cortex and pith not mucilaginous;

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

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.

11–14(–16) per areole, white to straw yellow, glabrous;

radial spines 10–12 per areole, whitish to pale yellowish tan, needlelike, 20 mm, stiff;

central spines 1–2(–4) per areole, ± porrect or 1 ascending and 1 descending, straight or slightly curved, 10 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.

3–4 × 2.5–3.5 cm;

outermost tepal margins densely minutely fimbriate (at 10x);

inner tepals greenish white to greenish yellow, 14–17(–25) × 2–3 mm;

stigma lobes yellow-green to pale green, 2–3 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.

whitish green proximally, pale green distally with pale rose-purple on sunlit portions, obovoid to clavate, 15–26 × 7.5–15 mm, juicy only in fruit walls;

floral remnant 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 or orange, 1.1–1.3 × 0.9 × 0.8 mm, pitted;

testa intermediate, anticlinal cell walls undulate, interstices much narrower than pit diam., pits deeply concave, elongate.

= 22.

= 22.