Opuntia humifusa |
Opuntia macrorhiza |
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devil's-tongue, eastern prickly-pear |
grassland pricklypear, plains prickly pear, plains twistspine pricklypear, twistspine pricklypear, western pricklypear |
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Habit | Shrubs, forming clumps or often prostrate, usually only 1 or 2 stem segments tall, to 0.5 m (except in Florida where they may be erect and reach to 2+ m with short trunk), flattened to obovoid, sometimes from tuberlike rootstocks. | Shrubs, forming clumps, 7.5–16 cm, sometimes from tuberlike rootstocks. | ||||
Stem | segments not disarticulating, dark or bright shiny green, wrinkling when stressed, circular to broadly oblong to obovate, 5–17.5 × 4–12 cm, fleshy, usually tuberculate, glabrous; areoles 4–6 per diagonal row across midstem segment, oval to circular, 2–4 mm diam., not raised, sometimes somewhat sunken; wool tan to brown. |
segments not easily detached, dark dull green, often cross wrinkled when stressed, flattened, obovate to circular, 5–11 × 3.5–7.5 cm, fleshy (to flabby and cross wrinkled when stressed), tuberculate, glaucous; areoles 5–6(–8) per diagonal row across midstem segment, oval to subcircular, 2–4 mm diam.; wool tan. |
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Spines | often absent or 1–2(–3) per areole, spreading, whitish to brownish, terete, straight, and usually stout, 25–60 mm; occasionally also 1 deflexed spine present. |
(0–)1–4 per areole, usually in distal areoles, erect to spreading, white to red-brown, acicular, straight, terete or 1 flattened, ± stout (0.5 mm diam. at base), longest to 60 mm. |
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Glochids | in dense crescent of adaxial edge of areole and in dense tuft overtopping crescent in age, yellow to red-brown, to 4 mm. |
in dense tuft, pale yellow, tan to red-brown, aging brown, to 5 mm. |
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Flowers | inner tepals pale to bright yellow throughout, 20–30 mm diam.; filaments yellow to orange; anthers pale yellow to cream; style and stigma lobes white. |
inner tepals yellow with red basal portions, 25–40 mm; filaments pale yellow; anthers yellow; style white; stigma lobes cream to yellowish. |
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Fruits | greenish, tardily becoming apricot to brownish red, elongate, 30–50 × 12–20 mm, fleshy, tapering at base; pulp green and sour, becoming reddish and sweet under ideal conditions; areoles 10–18. |
green to yellowish to dull red, stipitate, elongate-obovoid, 25–40 × 15–28 mm, fleshy, glabrous; areoles 16–28. |
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Seeds | tan, 3.5–4.5 mm diam., thickish; girdle protruding to 1 mm. |
tan, subcircular, 4–5 mm, thickish, warped; girdle broad, protruding to 0.5 mm. |
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2n | = 44. |
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Opuntia humifusa |
Opuntia macrorhiza |
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Phenology | Flowering late spring (May–Jun). | |||||
Habitat | Plains, chaparral, grassy woodlands, coniferous forests, sandy to loamy soils | |||||
Elevation | 100-2300 m (300-7500 ft) | |||||
Distribution |
AL; AR; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; WI; WV; ON
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AR; AZ; CO; KS; MO; NM; OK; TX; UT; Mexico (Chihuahua)
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Discussion | Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Opuntia macrorhiza hybridizes with the hexaploid O. engelmannii (apparently var. lindheimeri) forming the pentaploid O. ×edwardsii V. E. Grant & K. A. Grant. This hybrid is a small subshrub, 20–40 cm, with a mixture of widely spaced, unequal glochids and closely spaced, shorter glochids. Its major spines are gray, and its tepals are yellow or yellow with red bases. Those characteristics are similar to one parent or the intermediate of the two putative parents reported from Blanco and Guadalupe counties, central Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4, p. 130. | FNA vol. 4. | ||||
Parent taxa | Cactaceae > subfam. Opuntioideae > Opuntia | Cactaceae > subfam. Opuntioideae > Opuntia | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Cactus humifusus | O. compressa var. macrorhiza, O. mesacantha var. acrorhiza | ||||
Name authority | (Rafinesque) Rafinesque: Med. Fl. 2: 247. (1830) | Engelmann: Boston J. Nat. Hist. 6: 206. (1850) | ||||
Web links |
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