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. 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. Glochids in inconspicuous to small adaxial tuft, yellow to brown, 0.5-2 mm. 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. 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. 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. 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.

Plant: tree or shrub, sparsely to much-branched, 1-2(-4) m tall; STEM segments firmly attached, cylindric, 10-30 (-50) cm long, 2-2.5(-3) cm in diam.; tubercles prominent, narrow to broad, 1.5-4.5 cm long. AREOLES white-, yellowish- to tan-felty, aging gray-black, elliptic to subcircular, 4-5.5 mm long, 4-5 mm wide Leaves: SPINES mostly in distal areoles, 6-20(-30) per areole, often with 0-5 short bristle-spines at areole margins; sheaths white to grayish with yellow to golden tips, baggy to more tight-fitting; major apical spines terete, ascending-divergent, yellow or tan to deep red-brown, aging gray, the central one longest, 12-30(-38) mm long; major basal spines subterete to flattened, deflexed to divergent, the central one longest, 12-30(-35) mm long. GLOCHIDS yellow to brown, in inconspicuous small apical tuft, 0.5-2 mm long Flowers: inner tepals bright yellow to bronze to brick-red, spatulate, apiculate-emarginate, 2-3 cm long; filaments dark red, the anthers yellow; style and stigmas white to light green Fruit: at maturity tan, obconic to ellipsoid, the basal tubercles longest, dry, with apical flange above shallow umbilicus, 1.5-3.5 cm long, 1.5-2 cm in diam., densely to sparsely spiny, rarely spineless; areoles 12-30; SEEDS 3.5-5 mm long, 3-4.5 mm wide, pale yellow to tan, angular or squarish in outline, warped, the sides smooth but each with 2-4 large depressions, the girdle smooth REFERENCES: Pinkava, Donald J. 1999. Cactaceae. Ariz. – Nev. Acad. Sci. 32(1).