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

Habit Plants unbranched (very rarely branched).
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.

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.

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.

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.

Seeds

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

testa cells flat or very slightly convex.

2n

= 22.

Echinocactus texensis

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.)

Distribution
from FNA
NM; TX; Mexico (Coahuila, Durango, Nuevo León, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
Parent taxa Cactaceae > subfam. Cactoideae > Echinocactus
Sibling taxa
E. horizonthalonius, E. polycephalus
Synonyms Homalocephala texensis
Name authority Hopffer: Allg. Gartenzeitung 10: 297. (1842)
Source Flora of North America vol. 4, p. 190.
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