Opuntia polyacantha |
Opuntia tortispina |
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hair-spine prickly pear, panhandle prickly pear, plains prickly pear, starvation prickly-pear |
plains pricklypear |
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Habit | Shrubs, low, 10–25 cm, with ± prostrate branches. | Shrubs, low, to 0.4 m, creeping from clumps, sometimes from thickened rootstocks. | ||||||||||||||||
Stem | 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 easily detached, pale green to deep green, graying with age, wrinkled when stressed, flattened, broadly obovate to ovate, 6.5–15 × 4–10 cm, tuberculate, glossy, glabrous; areoles 6–9 per diagonal row across midstem segment, oval, obovate, or subcircular, 2.5–5 × 1.5–4 mm; wool tan, aging brown. |
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Spines | 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. |
1–9 on most areoles to only on distal 1/2 of stem segment, white to gray with pale brown tips and bases, sometimes brown throughout; central spines 1–3, all deflexed or 1–2 porrect or ascending, terete or flattened, occasionally spirally twisted, 25–70 mm; small spines (2–)3–6(–8) strongly deflexed, usually slender, even bristlelike, 5–15 mm. |
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Glochids | 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. |
forming a well developed adaxial tuft, yellow to brownish white, to 6 mm. |
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Flowers | 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 to gold, commonly darker to red near base, broadly spatulate, 30–40 mm, apiculate; filaments usually pale yellow; anthers yellow; style whitish to pale green; stigma lobes greenish. |
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Fruits | 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. |
purple-red, oval to broadly ovate, subspheric or short ovoid, bases not narrowed, 30 × 20–25 mm, fleshy, base not narrowed, glabrous, spineless or nearly so; umbilicus deep; areoles 18–30. |
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Seeds | tan to gray, flattened, warped, oblong to subcircular, 3–7 × 2–4 mm; girdle protruding 1–2 mm. |
whitish to tan, irregularly shaped, flattened, 4–6 × 3–4 mm; girdle protruding 1–2 mm. |
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2n | = 44, 66. |
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Opuntia polyacantha |
Opuntia tortispina |
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Phenology | Flowering spring–early summer (Apr–Jul). | |||||||||||||||||
Habitat | Grass-lands, pinyon-juniper-oak woodlands, sandy or shaley flats, rocky hills | |||||||||||||||||
Elevation | 1400-1800 m (4600-5900 ft) | |||||||||||||||||
Distribution |
AZ; CA; CO; ID; KS; MT; ND; NE; NM; NV; OK; SD; TX; UT; WY; AB; SK; n Mexico
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CO; KS; NE; NM; OK; TX; WY |
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Discussion | Varieties 5 (5 in the flora). Populations of Opuntia polyacantha with spines few or absent (especially var. hystricina) were the basis for several names including O. juniperina, O. utahensis, and O. rhodantha. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Opuntia tortispina is apparently of hybrid origin. It has intermediate character states from its putative parents, O. macrorhiza (fleshy and spineless fruits) and O. polyacantha (areoles with basal deflexed spines and barrel-shaped fruits). The spirally twisted spines, which the specific epithet implies, are not at all characteristic for this species. When O. tortispina and O. cymochila are considered conspecific, the former has priority, as first selected by N. L. Britton and J. N. Rose (1919–1923, vol. 1). One favored hypothesis as to the origins is that the O. humifusa-O. macrorhiza-O. pottsii complex spread across the United States from the east coast to Arizona. Opuntia polyacantha originated in north-central Mexico and spread northward. Tetraploid O. macrorhiza came into contact with the east flank of O. polyacantha and hybridized (probably repeatedly, even at present), producing the highly variable taxon referred to here as O. tortispina, which then spread eastward onto the plains. Opuntia tortispina has hexaploid members, presumably from unions of reduced and unreduced gametes. Those hexaploids apparently hybridize with hexaploid O. phaeacantha and add further to variation of O. tortispina. Many of these variations have been formally named or since treated as synonyms of O. macrorhiza. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4. | FNA vol. 4, p. 132. | ||||||||||||||||
Parent taxa | Cactaceae > subfam. Opuntioideae > Opuntia | Cactaceae > subfam. Opuntioideae > Opuntia | ||||||||||||||||
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Synonyms | Cactus ferox, Tunas polyacantha | O. cymochila, O. mackensenii, O. tortispina var. cymochila | ||||||||||||||||
Name authority | Haworth: Suppl. Pl. Succ., 82. (1819) | Engelmann & J. M. Bigelow: Proc. Amer. Acad. Arts 3: 293. (1856) | ||||||||||||||||
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