Flora of North America species comparison

diffuse, upper portion not enlarged.

upper portion of primary root somewhat thickened and succulent proximally, otherwise fibrous.

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 or spheric, 4–8 × 4–8 cm, ± flaccid;

tubercles 6–24 mm;

axils appearing naked;

cortex and pith mucilaginous;

latex absent.

(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.

9–31(–34) per areole, white, usually tipped brown;

radial spines 8–30 per areole, in 1 series, glabrous (puberulent in first year flowering plants);

lateral spines bristlelike, 7–11 mm, stiff, longest and thickest of spines;

adaxial spines often darker;

central spines 1–4(–7) per areole, porrect or strongly projecting, 1 or all hooked, (5–)12–14(–21) 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(–5.2) × 2.2–4.5(–7.5) cm;

outer tepal margins conspicuously fringed;

inner tepals rose-pink or magenta [white], margins often paler;

stigma lobes yellow or pale green (rarely reddish).

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

floral remnant persistent.

green or dull purple, spheric to ovoid or obovoid, (9–)13–20(–28) × (6–)7–1.9(–26) mm, juicy throughout;

floral remnant persistent.

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

testa hard;

interstices equaling pit diameters;

pits bowl-shaped.

black, 1.3–1.5 mm, pitted;

testa hard, anticlinal cell walls straight (not undulate);

interstices conspicuously narrower than pit diameters;

pits bowl-shaped.

= 22.

= 22.