Buck Horn Cholla

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.

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.

Opuntia acanthocarpa Engelmann & J. M. Bigelow, Proc. Amer. Acad. Arts 3: 308. 1856

The buckhorn cholla (Cylindropuntia acanthocarpa) is an open and spreading woody cactus, up to 1 m tall. The gray-green stems, also called "joints", are cylindrical, 5-30 cm long and 17-20 mm in diameter with tubercles or nodules. Each tubercle has a cluster of stiff spines, which are covered with loose papery sheaths. The flowers are up to 5 cm long and range from yellow to purple-red with shades in between. The fruits are obovoid, dry, shriveled and spiny and drop off later in the season. The seeds are light yellowish to gray-brown, 3.5 to 4 mm. long. Varieties of C. acanthocarpa (var. acanthocarpa, var. coloradensis, var. major and var. thornberi) are found in Arizona, California, Nevada and Utah; in Arizona, all of the varieties are protected plants.

In the Southwest the Hualapai and Pima harvested the unopened flower buds of buckhorn cholla with two long sticks. The sticks were used to grab the mature buds and twist them off into a large flat basket or bucket. The spines are then removed prior to cooking. Traditionally the buds were baked in an earthen pit, lined with stones, and heated with mesquite (Prosopis velutina) firewood. Then the buds were eaten right away or dried and stored for future use. Pima individuals who had stomach troubles were put on a special diet of these buds made into gruel. Some individuals still gather buckhorn cholla today.

Cylindropuntia acanthocarpa, commonly referred to as buckhorn cholla, is a cholla native to the Mojave, Sonoran, and Colorado Deserts of North America. Along with Cylindropuntia bigelovii (the "teddy bear" cholla), it is the most common cholla found in these deserts.