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.

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.

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.

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.

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.

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

floral remnant persistent.

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, 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 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.

= 66.

= 22.