5. Cylindropuntia fulgida (Engelmann) F. M. Knuth in C. Backeberg and F. M. Knuth, Kaktus-ABC. 126. 1935.
Opuntia fulgida Engelmann, Proc. Amer. Acad. Arts 3: 306. 1856
Trees 1-3 m; trunk divaricately branching; crown many branch-ed, spreading. Stem segments whorled or subwhorled, gray-green, often drying blackish, ± spiny throughout, terminal ones easily dislodged, 6-16(-23) × 2-3.5 cm; tubercles salient, broadly oval, 0.8-1.3(-1.9) cm; areoles obdeltate, 5-7(-10) × 2.5-4 mm; wool gold to tan, aging gray to black. Spines 0-12(-18) per areole, at most areoles to nearly absent, yellowish, sometimes also pale pinkish, aging brown, interlaced or not with spines of adjacent areoles; abaxial spines erect to deflexed, spreading, flattened basally, the longest to 3.5 cm; adaxial spines erect or spreading, terete to subterete, longest to 2.5 cm; sheaths uniformly whitish, yellowish to golden, baggy. Glochids in adaxial tuft, sometimes also scattered along areole margins, yellow, 1-3 mm. Flowers: inner tepals usually reflexed, pink to magenta, obovate to ligulate, 12-16 mm, apiculate emarginate; filaments pale pink to magenta; anthers white to cream; style pinkish; stigma lobes whitish to pale yellow. Fruits proliferating, forming long, branching, pendent chains, at maturity gray-green, often stipitate, obconic, fleshy, shallowly tuberculate, usually spineless; basal fruits 32-55 × 23-45 mm; terminal fruits 2-3.3 × 1.3-2.3 cm; tubercles becoming obscure; umbilicus to 8 mm deep; areoles 18-35. Seeds pale yellow to brownish, angular to very irregular in outline, warped, 1.9 × 1.5-3.5 mm, sides with 1-2 large depressions, hilum pointed; girdle smooth.
Varieties 2 (2 in the flora): sw United States, nw Mexico.
Intermediates are known between the varieties, which are largely sympatric in northern portion of range of the species.
Cylindropuntia fulgida forms hybrids with C. spinosior (see 6. C. ×kelvinensis) and C. leptocaulis. Hybrids, which are rare in south-central Arizona, have stems of intermediate diameter, (0-)1-5 spines per areole, one spine much longer than others, and spineless, yellowing, and often reddish fruits in chains of four to six, or more.