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biznaga-tonel manca caballo, devil's pincushion, horse crippler

cluster barrel cactus, echinocactus

Habit Plants unbranched (very rarely branched). Plants erect, branched or unbranched, forming compact mounds of 30+ branches, not deep-seated in substrate (or deep-seated in E. texensis and, if plants immature or at high altitude, in E. horizonthalonius).
Roots

diffuse or short taproots.

Stems

pale gray-green (desert populations) to grass green (eastern populations), above-ground portion flat-topped, hemispheric in old age but usually deep-seated, flush with soil surface, 10–30 × 10–30 cm;

ribs 13–27, very prominent, straight, vertical, or sinuous on desiccated plants, crests ± sharp, without depressions between areoles but sometimes areoles recessed part way into rib.

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.

Spines

(6–)7–8 per areole, mostly decurved or 1 porrect and straight, pale tan, pink, reddish to gray, terete to flattened, annulate, not hiding stem surfaces, minutely canescent with laterally compressed unicellular trichomes;

radial spines (5–)6–7 per areole;

central spine 1 per areole, porrect or descending, straight or distally decurved, (20–)40–60(–80) × 1.5–4(–8) mm.

(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.

Flowers

5–6 × 5–6 cm; inner tepals bright rose-pink to pale silvery-pink, proximally orange to red, (15–)28–32 × (3–)6(–9) mm, margins usually erose;

stigma lobes pink to pinkish white.

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.

Fruits

indehiscent (rarely rupturing irregularly), scarlet or crimson, spheric to ovoid, 15–50 × 15–40 mm, fleshy, surfaces not hidden by widely spaced hairs in axils of scales;

scales 13–21, distal scales spine-tipped, minutely puberulent.

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.

Seeds

black, spheric-reniform or irregularly obovoid, 2.5–3 mm, glossy;

testa cells flat or very slightly convex.

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

testa cells convex or flat.

x

= 11.

2n

= 22.

Echinocactus texensis

Echinocactus

Phenology Flowering late spring.
Habitat Chihuahuan Desert, grasslands, openings in oak woodlands, Tamaulipan thorn scrub, deep soils, saline flats, low limestone hills
Elevation 0-1400 m [0-4600 ft]
Discussion

The western, desert populations of Echinocactus texensis, unlike the eastern plants, have longer central spines that project stiffly outward and can flatten off-road vehicle tires or seriously injure a large mammal stepping on them. A dense cover of ephemeral herbs or shallow blanket of snow can hide this species completely from view.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 6 (3 in the flora).

With the exception of the much-branched Echinocactus polycephalus, species of Echinocactus in the flora area are almost never branched, and will die instead of producing a lateral bud when the apex is injured. Smaller than normal fruits of Echinocactus are usually aborted and hollow as the result of infestation by insect larvae (M. Chamberland, pers. comm.).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Distribution
from FNA
NM; TX; Mexico (Coahuila, Durango, Nuevo León, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from USDA
sw United States; Mexico
[BONAP county map]
Parent taxa Cactaceae > subfam. Cactoideae > Echinocactus Cactaceae > subfam. Cactoideae
Sibling taxa
E. horizonthalonius, E. polycephalus
Subordinate taxa
E. horizonthalonius, E. polycephalus, E. texensis
Key
1.Inner tepals yellow; plants many branched (except in very young adults); w Arizona, s Nevada, se California, MexicoE. polycephalus
1.Inner tepals pink, magenta, or proximally red and distally pink; plants unbranched (rarely few branched); c to s Arizona, New Mexico, Texas, Mexico→ 2
2.Ribs (7-)8(-9), crests broadly rounded, never keeled; stems flat-topped or hemispheric to stoutly cylindric; fruit surfaces hidden by abundant wool at maturity; spines and bract tips glabrous (use lens)E. horizonthalonius
2.Ribs 13-27, crests narrow, ± keeled; stems flat-topped to hemispheric; fruit surfaces exposed at maturity, bright red; spines and bract tips densely puberulent with ± matted, strap-shaped, unicellular hairs (use at least 8× lens)E. texensis
Synonyms Homalocephala texensis Homalocephala
Name authority Hopffer: Allg. Gartenzeitung 10: 297. (1842) Link & Otto: Verh. Vereins Beförd. Gartenbaues Königl. Preuss. Staaten 3: 420. (1827)
Source Flora of North America vol. 4, p. 190. Flora of North America vol. 4, p. 188.
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