Flora of North America species comparison

segments not easily detached, green, elliptic to narrowly to broadly obovate to circular, 4–27 × 2–18 cm, low tuberculate;

areoles 4–14 per diagonal row across midstem segment, subcircular, 3–6 mm;

wool tan to brown.

segments not disarticulating, blue-green, flattened, obovate to circular, 13–21 × 11.5–19 cm, nearly smooth, glabrous;

areoles 7–10 per diagonal row across midstem segment, subcircular to elliptic, with basal ridge, 3–6 × 2.5–4 mm;

wool tan, aging grayish white.

at all or only distal areoles of stem segment, terete to flattened, stout to acicular to bristlelike, straight to curling, of 1 or 2 kinds;

if 1 kind: 0–18 per areole, spreading and curling in various directions, sometimes straight, erect, ascending to deflexed, yellow to dark brown to black, turning gray, pink-gray to gray-brown, longest (35–)40–90(–185) mm;

if ± 2 kinds: major spines (0–)1–5, reflexed to porrect, yellow-brown to brown to gray, longest 20–150 mm;

minor spines (0–)5–11, deflexed, white to white-gray, longest 4–16 mm.

absent or usually in distal areoles to evenly distributed over entire stem segment, yellow, aging red-brown to blackish, straight or weakly curved, ± acicular, deflexed, or some erect in marginal areoles;

larger spines 0–7 per areole, terete or basally flattened, 25–45 mm, usually accompanied by few straight to wavy bristle-spines.

inconspicuous, in narrow, tidy crescent at adaxial edge of areole or in broad, brushy crescent and tuft, yellow to reddish, aging brown, to 10 mm.

crowded in narrow crescent along adaxial margins, longer toward base of areole margins, subapical tuft absent or poorly developed, yellow, aging reddish brown, to 14 mm.

inner tepals yellow to magenta throughout, 25–40 mm;

filaments white, yellow, or red to magenta (flowers may superficially appear bicolored);

anthers yellow;

style white to pale pink;

stigma lobes green.

inner tepals yellow (sometimes with reddish blush near base), abaxially reddish streaked along midveins, broadly spatulate-apiculate, 18–30 mm;

filaments white to yellow;

anthers;

style and stigma lobes white, yellowish, or pale green.

tan to brown, ± cylindric, 15–45 × 12–25 mm, dry at maturity, glabrous, sometimes burlike;

areoles 10–33, each or only distal areoles bearing 3–16 spines, 4–20 mm.

red, barrel-shaped, 30–60 × 18–40 mm, fleshy (often mummifying), glabrous, spineless;

umbilicus 6–9 mm deep;

areoles 40–68.

tan to gray, flattened, warped, oblong to subcircular, 3–7 × 2–4 mm;

girdle protruding 1–2 mm.

yellowish, 3.5–4 × 3–3.5 mm, 1.5–1.8 mm thick, reniform to subcircular, flattened, often warped;

girdle protruding 0.1–0.5 mm.

= 22.