Flora of North America species comparison

diffuse, upper portion not enlarged.

short, obconic taproots;

secondary roots diffuse.

depressed-spheric to short cylindric, (1–)2–3.5 × (1.4–)2–4(–7) cm, firm;

tubercles 3–6(–8) × 2–3 mm;

axils without evident hairs;

cortex and pith not mucilaginous;

latex clear or slightly milky, sporadic, only in outer cortex.

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.

(26–)40–60(–90) per areole, in several series but all equally thin, mostly appressed, white or very pale pink, often minutely tipped pinkish brown, innocuous, bristlelike, 0.6–5(–6) × 0.05–0.1 mm, glabrous to plumose, all interpreted as radial, innermost spines shortest;

central 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.

0.9–1.5(–2) × 0.8–1.3(–1.8) cm;

outermost tepal margins entire (or minutely and irregularly lacerate);

inner tepals white or cream, usually with sharply defined midstripes of green, yellow, tan, pink, pale purple, or reddish, 4.5–8 × 1.5–2.7 mm;

stigma lobes yellow or pale yellow-green to green, 0.3–1 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.

scarlet, cylindric or clavate, 10–20(–25) × (3–)4–8(–11) mm, juicy mostly in fruit walls;

floral remnant persistent.

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

floral remnant weakly persistent.

black, 1–1.2[–1.4] × 0.8[–1.1] × 0.8 mm, pitted;

testa hard;

interstices equaling 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.

= 22.

= 22.