Flora of North America species comparison

diffuse or short taproots.

gray-green to yellow-green, spheric to short cylindric, 15–40 × (9–)15–30 cm;

ribs 11–25, usually vertical, or somewhat helically curving around stem, rib crests not constricted between areoles (slightly so when desiccated), sharp, with flat sides.

unsegmented, gray-blue, gray-green, yellow-green, or grass green, flat-topped spheric to short cylindric, 4–40(–45)[–250] × 8–30[–80] cm, apical region appearing copiously woolly (shortly velvety in E. texensis) [glabrous];

ribs (7–)8–27[–60+], very prominent, straight (or only slightly undulate), sometimes helically curving around stems, broadly rounded to nearly keeled, rib crests uninterrupted or ± constricted between areoles;

areoles widely spaced or confluent with age, nearly circular to oblong, with fertile portion as short, broad adaxial prolongation confluent with spine cluster;

areolar glands absent;

cortex and pith hard, not mucilaginous.

10–19 per areole, straight to curved but not hooked, often twisted, red to straw colored, aging gray, flattened to abaxially ridged, annulate-ridged, nearly obscuring stem surfaces, glabrous to canescent with minute, white, unicellular trichomes often obscuring underlying spine color;

radial spines 6–14 per areole;

central spines 4, abaxial frequently longest, straight to somewhat recurved.

(5–)7–19 per areole, straw colored, pink, red, gray, tan, or brown, conspicuously annulate-ridged, rigid, stiff;

radial spines 5–14 per areole, straight to curved, 2–5 cm;

central spines 1–4 per areole, straight to curved, terete, flattened, or abaxially ridged.

5.5–5.8 × 4–6 cm, narrower when spines restrict flower from opening fully;

inner tepals bright yellow, color uniform from base to apex, 24–26 mm, sparsely, minutely toothed;

stigma lobes bright yellow.

diurnal, near stem apex, near adaxial edges of short adaxial extensions of areoles, broadly funnelform to nearly salverform (more narrowly funnelform in E. texensis);

outer tepals margins entire, apically spinose;

inner tepals yellow or pink to magenta, 2.4–3.2 × 0.3–1.5 cm, margins entire, serrate, toothed, or erose;

ovary scaly, spineless, copiously woolly, with white or pale tan hairs from areoles hiding ovary and flower tube at anthesis;

scales 8–60, margins entire or fimbriate, spine-tipped;

stigma lobes 6–14(–17), yellow, pink, or olive, 1–4.5 mm.

dehiscent through basal abscission pore, ovoid, surfaces largely hidden by hairs in axils of scales and long areolar trichomes of stem apex, usually drying to tan shell before seed dispersal, 15–40 mm;

scales abundant, yellow to reddish throughout, or yellow with reddish midstripes, flat, tips spinelike, glabrous or canescent.

either indehiscent or rupturing irregularly, or tardily dehiscent through basal abscission pore, whitish tan to pinkish (bright red in E. texensis), spheric to ovoid or ovoid-cylindric, 10–50 × 10–40[–100] mm, usually nearly dry (strongly succulent in E. texensis), many scaled;

axils of scales copiously woolly (wool hiding surface of fruits except in E. texensis), spineless, distal scales spine-tipped;

pulp red;

floral remnant persistent.

dark maroon to black, ± obovoid-reniform or comma-shaped, 2.4–4.7 mm, smooth and shiny or granular and dull from protruding surfaces of testa cells;

testa cell surfaces sometimes hemispheric to hexagonally faceted.

reddish brown to black, spheric, or subreniform to obovoid, 2.4–4.7 mm, shiny or dull;

testa cells convex or flat.

= 11.