Cylindropuntia acanthocarpa |
Cylindropuntia ×kelvinensis |
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buck-horn cholla |
kelvin pricklypear |
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Habit | Trees or shrubs, sparsely to densely branched, 1–2(–4) m. Stem segments firmly attached, cylindric, 10–30(–50) × 2–2.5(–3) cm; tubercles prominent, narrow to broad, 1.5–4.5 cm; areoles elliptic to subcircular, 4–5.5 × 4–5 mm; wool white or yellowish to tan, aging gray-black. | Trees 1.5–2 m; trunk commonly branched; crown open to compact usually bearing whorled branches. | ||||||||||||
Stem | segments often easily dislodged, if terminal, green or purple, 5–13 × 1.8–3 cm; tubercles prominent, broadly oval, 0.7–1.2(–1.5) cm; areoles obdeltate to rhombic, 4.5–6 × 3–5 mm; wool yellow, aging gray to black. |
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Spines | 6–20(–30+) per areole, often accompanied by 0–5 short bristlelike spines at areole margins, usually in distal areoles; major abaxial spines deflexed to divergent, subterete to flattened; major adaxial spines ascending-divergent, terete, yellow or tan to deep red-brown, aging gray, the central spine longest, 12–30(–38) mm; sheaths white to grayish with yellow to golden tips, baggy to tight fitting. |
0–8(–13) per areole, sometimes with 1–3 bristlelike spines along areole margins at most areoles, usually slightly interlacing with spines of adjacent areoles, yellowish to tan, sometimes with pinkish hue, to red-brown and partially gray coated, aging brown-gray to gray; major abaxial spines angular-flattened, usually reflexed, the longest to 30 mm; major adaxial spines subterete, erect-divergent, the longest to 18 mm; sheaths uniformly whitish or tipped yellow to gold, slightly baggy. |
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Glochids | in inconspicuous to small adaxial tuft, yellow to brown, 0.5–2 mm. |
in inconspicuous adaxial crescent, yellow, to 1 mm. |
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Flowers | inner tepals bright yellow to bronze to brick red, spatulate, 20–30 mm, apiculate-emarginate; filaments red; anthers yellow; style and stigma lobes white to light green. |
inner tepals rose to magenta, spatulate, 18–25(–30) mm, emarginate-apiculate; filaments deep rose; anthers yellow; style white, tinged red-purple distally; stigma lobes white with hint of green. |
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Fruits | tan at maturity, obconic to ellipsoid, 15–35 × 15–20 mm, dry, tuberculate, densely to sparsely spiny (rarely spineless), with apical flange above shallow umbilicus; basal tubercles longest; areoles 12–30. |
usually sterile, sometimes forming short chains, yellow-green to yellow, sometimes purplish, 25–45 × 15–22 mm, fleshy, tuberculate, spineless; tubercles progressively longer toward fruit apex; umbilicus 4–7 mm deep; areoles 32–44. |
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Seeds | pale yellow to tan, angular or squarish in outline, warped, 3.5–5 × 3–4.5 mm, sides smooth, each with 2–4 large depressions; girdle smooth. |
pale yellow, orbicular to angular or squarish in outline, flattened to warped, 3.5–4 × 3–4 mm, sides with 0–2 large depressions; hilum sometimes pointed; girdle smooth. |
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2n | = 22, 33. |
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Cylindropuntia acanthocarpa |
Cylindropuntia ×kelvinensis |
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Phenology | Flowering spring (Apr–Jun). | |||||||||||||
Habitat | Sonoran desert scrub, edges of grasslands, rocky flats and slopes, rolling hills | |||||||||||||
Elevation | 500-1000 m (1600-3300 ft) | |||||||||||||
Distribution |
AZ; CA; NV; UT; n Mexico
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AZ |
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Discussion | Varieties 4 (4 in the flora). Cylindropuntia acanthocarpa hybridizes with C. abyssi, C. echinocarpa (= C. ×deserta), C. bigelovii (= C. ×campii), C. leptocaulis (see C. ×tetracantha), C. ×multigeniculata, C. spinosior, C. versicolor, and C. whipplei (= C. congesta). Hybrids of C. acanthocarpa and C. ×multigeniculata are more open in habit, with longer stem segments than C. ×multigeniculata and with reddish filaments like C. acanthocarpa. (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. 108. | ||||||||||||
Parent taxa | Cactaceae > subfam. Opuntioideae > Cylindropuntia | Cactaceae > subfam. Opuntioideae > Cylindropuntia | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Opuntia acanthocarpa | Opuntia kelvinensis | ||||||||||||
Name authority | (Engelmann & J. M. Bigelow) F. M. Knuth: in C. Backeberg and F. M. Knuth, Kaktus-ABC, 124. (1935) | (V. E. Grant & K. A. Grant) P. V. Heath: Calyx 4: 142. (1994) | ||||||||||||
Web links |