Flora of North America species comparison

diffuse.

unsegmented, gray-green to yellowish or bronze-tinted green, spheric to short cylindric, 5–10(–24) × (1.8–)2.5–6.5(–8) cm, usually white woolly at apex;

tubercles prominent, not confluent into ribs, tightly packed in vertical, sprialing rows as if tuberculate ribs, compressed conic, 7–12 × 4–7 mm, 8–18 mm diam. at base;

areoles adaxially elongated into long, narrow, conspicuous grooves extending into axils of tubercles, usually short woolly;

areolar glands absent;

cortex and pith not mucilaginous; specialized, yellow, sticky layer beneath old bark.

9–17[–26] per areole, white, gray, brown, or black, acicular, straight;

radial spines 9–15[–25] per areole, with bulbous bases, 6–17 mm;

central spines [0–]6(–8) per areole, terete with bulbous bases.

diurnal, at stem apex, at axillary end of areolar groove, showy, short funnelform, 2.5–3.2 × 3–5.5 cm;

outer tepals whitish or magenta to purplish, to 25 × 10 mm, margins entire (sometimes irregularly, minutely denticulate);

inner tepals bright rose-pink or magenta, 15–32 × 5–11 mm, margins entire;

ovary smooth, spineless;

stigma lobes 4–7, white to cream, 2–4 mm.

dehiscent along vertical slits or indehiscent, green to white (slightly pinkish near base), becoming tan or greenish brown, spheric, 4–10 × 4–8 mm, dry and papery, smooth, spineless;

pulp absent;

floral remnant deciduous.

black to gray, obovoid or pyriform, 1.1–1.6 × 0.8–1.2 mm, papillate;

testa cells strongly convex.

= 11.