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

Photo is of parent taxon
Habit Plants unbranched (very rarely branched). Trees, shrubs, or short perennial plants, solitary to forming mats, columnlike or barrel-shaped to spheric stem succulents, sometimes geophytic or epiphytic, erect to prostrate, scrambling, climbing, or hanging, freely branched or unbranched.
Roots

diffuse, taproots, or tuberlike, sometimes adventitous.

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.

segmented or unsegmented, usually conspicuously succulent with thick cortex and pith, surface usually ribbed or tuberculate, usually somewhat woody with wood confined to internal ring, bark sometimes becoming proximally hardened and woodlike;

areoles circular to linear [protracted into finger-shaped shoots in Neoraimondia of South America], hourglass-shaped in some genera, with spiny portion separated from flowering portion by a groove in the stem surface, spiny areoles completely separate from flowering areoles in some genera, bearing 0–90 spines, glochids absent.

Leaves

absent or rudimentary and microscopic or nearly so, less than 1 mm.

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.

acicular, subulate, daggerlike, ribbonlike, hairlike, or bristlelike, smooth, rough, striate, or annulate-ridged, glabrous (rarely pubescent), epidermis intact, not separating as sheath.

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 to nocturnal, bisexual (rarely unisexual or functionally so), solitary in areoles (rarely several), radially symmetric (rarely bilateral), sessile, broadly salverform, urceolate, funnelform, or long tubular;

flower tube epigynous, usually conspicuous, adnate to upward extension of stem surrounding ovary, 0.2–15[–30] cm;

triangular leaflike bracts or small scales sometimes present on ovary and flower tube;

nectary often apparent, forming open chamber surrounding base of style.

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.

dehiscent or indehiscent, depressed-spheric or spheric to long clavate, juicy, fleshy, or dry;

perianth persistent or deciduous.

Seeds

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

testa cells flat or very slightly convex.

1–3000+, yellowish, reddish, brown, or black, spheric, comma-shaped, lenticular-reniform, pyriform, or obovoid, 0.4–5 mm, rarely strophiolate, never arillate.

2n

= 22.

Echinocactus texensis

Cactaceae subfam. Cactoideae

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.)

Genera ca. 111, species ca. 1500 (28 genera, 121 species in the flora).

Subfamily Cactoideae is the most diverse group of the Cactaceae, in terms of size, architecture, habitat, and habit. The vast majority of North American species are xerophytic, with columnar to spheric or barrel-shaped stems. A few are geophytic, that is, stems are mostly deep-seated in the soil substrate, often with the plant consisting mostly of an enlarged taproot and the visible parts of the stems appearing nearly flush with the soil surface or nearly buried during drought, becoming taller and slightly more conspicuous only during the growing season. Fewer species still, are epiphytic, and those only in the tropical and subtropical regions of North America and South America.

In the following treatments, most authors have attempted to recognize varieties wherever current evidence is compelling. Where evidence is equivocal, our tendency has been to include greater variability within varieties and, hence, fewer formal trinomials. Unfortunately, in the absence of strong supporting evidence, herbarium specimens of cacti are usually inadequate for the purpose of making taxonomic decisions. As a consequence, some populations of conservation interest here have been placed into synonmy before critical studies have been conducted to determine quantitatively and objectively how distinct each population is, or which deserve varietal status. Authors do not intend to imply that other varieties should not eventually be recognized. More systematic work, including DNA research and field research of all variants, is needed as a prelude to reassessing the status of currently listed and proposed populations. Such populations need to be protected during the entire phase of analysis and reassessment.

(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]
Almost throughout New World from southern Canada to s South America; Rhipsalis disjunct to Africa; Madagascar; and Sri Lanka; some species in horticulture almost worldwide
Parent taxa Cactaceae > subfam. Cactoideae > Echinocactus Cactaceae
Sibling taxa
E. horizonthalonius, E. polycephalus
Subordinate taxa
Synonyms Homalocephala texensis
Name authority Hopffer: Allg. Gartenzeitung 10: 297. (1842) Eaton: Bot. Dict. ed. 4, 43. (1836)
Source Flora of North America vol. 4, p. 190. Flora of North America vol. 4.
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