Flora of North America species comparison

diffuse, upper portion not enlarged.

short, obconic taproots;

secondary roots diffuse.

nearly spheric to more often cylindric or long cylindric, 5–30 × 5–7 cm, firm;

tubercles 5–12 × 3–7 mm;

axils woolly, bearing 4–15 bristles (0 in young growth) as long as tubercles;

cortex and pith not 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.

14–26 per areole, pinkish or reddish brown to black, glabrous;

radial spines 11–22 per areole, usually white, bristlelike, 5–7 mm, stiff;

central spines (1–)3–4 per areole, abaxial 1 porrect, hooked, longer, stouter, adaxial central spines ascending with radial spines;

subcentral spines 0.

(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.

10–22 mm;

outermost tepals entire or short fringed;

inner tepals cream, usually with pinkish or reddish midstripes, longer in bisexual flowers, 5.4 mm diam.;

stigma lobes yellow to greenish yellow or brownish green, 8 mm.

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 scarlet, clavate or ovoid, 10–25(–35) × 10 mm, juicy only in fruit walls;

floral remnant persistent.

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

floral remnant weakly persistent.

black, 0.8 × 0.6 mm, pitted;

testa hard;

anticlinal cell walls straight (not undulate);

interstices conspicuously wider than pit diameters;

pits bowl-shaped.

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.

= 66.

= 22.