Opuntia polyacantha |
Opuntia fragilis |
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hair-spine prickly pear, panhandle prickly pear, plains prickly pear, starvation prickly-pear |
brittle prickly-pear, brittle prickly-pear cactus, little prickly-pear |
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Habit | Shrubs, low, 10–25 cm, with ± prostrate branches. | Shrubs, low, forming mats, 2–10 cm. | ||||||||||||||||
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 easily detached when terminal, dark green, subspheric to subcylindric, to flattened and elliptic obovate, (1.5–)2–5.5 × (1–)1.5–3 cm, low tuberculate (pronounced when dried), glabrous; areoles 3–5 per diagonal row across midstem segment, oval, 3 × 2.5 mm; wool white. |
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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. |
3–8 per areole, in most areoles spreading, gray with brown tips, straight, ± acicular, terete, the longest 8–24 mm; depressed spines at base of areoles 0–3, 1–3 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. |
in crescent at adaxial margin of areole, tan to brown, inconspicuous, to 3 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, sometimes basally red, 20–26 mm; filaments white or red; anthers yellow; style white; stigma lobes green. |
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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. |
tan, 10–30 × 8–15 mm, dry, glabrous; areoles 12–22, distal areoles bearing 1–6 short spines. |
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Seeds | tan to gray, flattened, warped, oblong to subcircular, 3–7 × 2–4 mm; girdle protruding 1–2 mm. |
tan to gray, flattened, warped, oblong to subcircular, 5–6 mm diam.; girdle protruding 1–1.5 mm. |
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2n | = 66. |
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Opuntia polyacantha |
Opuntia fragilis |
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Phenology | Flowering summer (late Jun-early Jul). | |||||||||||||||||
Habitat | Barren areas in grasslands, woodlands, sandy or gravelly soils, on outcrops of granite, limestone, or quartzite | |||||||||||||||||
Elevation | 0-2400 m (0-7900 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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AZ; CA; CO; IA; ID; IL; KS; MN; MT; ND; NE; NM; OK; OR; SD; TX; UT; WA; WI; WY; AB; BC; MB; ON; SK; Mich
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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 fragilis is a widespread, though inconspicuous, species; in many places, it flowers infrequently, if at all. Its easily detached stem segments are dispersed by animals and possibly water. (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. 146. | ||||||||||||||||
Parent taxa | Cactaceae > subfam. Opuntioideae > Opuntia | Cactaceae > subfam. Opuntioideae > Opuntia | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | Cactus ferox, Tunas polyacantha | Cactus fragilis, O. brachyarthra, O. fragilis var. brach | ||||||||||||||||
Name authority | Haworth: Suppl. Pl. Succ., 82. (1819) | (Nuttall) Haworth: Suppl. Pl. Succ., 82. (1819) | ||||||||||||||||
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