4. Cylindropuntia kleiniae (de Candolle) F. M. Knuth in C. Backeberg and F. M. Knuth, Kactus-ABC. 123. 1935.
Klein cholla, tasajillo
Opuntia kleiniae de Candolle, Mém. Mus. Nat. Hist. 17: 118. 1828; O. wrightii Engelmann
Shrubs scraggly, openly branched, 0.5-2.5 m. Stem segments usually alternate, green, 4-20 × 0.6-1.2 cm; tubercles obvious, 1-2.5 cm; areoles subcircular to oval, 2.5-3.5 × 2-3 mm; wool yellow, aging gray to black. Spines (0-)1-2(-4) per areole, at most areoles, straight to slightly arched, commonly deflexed, not obscuring stem, yellow to gray, tipped yellow, acicular, the longest 1-3 cm. Glochids in adaxial tuft, yellow, 0.5-2.5 mm. Flowers: inner tepals greenish basally to reddish bronze, tinged magenta apically, spatulate-apiculate, 15-25 mm; filaments greenish basally to bronze distally; anthers yellow; style greenish bronze; stigma lobes cream. Fruits green becoming red, obovoid to cylindric, 13-34 × 10-20 mm, fleshy, low tuberculate to smooth, spineless; tubercles subequal; umbilicus 3-6 mm deep; areoles 16-28. Seeds tan, squarish to oval, 4-5 × 3.5-4 mm, warped, sides smooth to lumpy; girdle broad, low-ridged. 2n = 44.
Flowering late spring-early summer (May-Jun). Chihuahuan Desert, creosote bush-mesquite flats, limestone rocky slopes; 800-1800 m; N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Durango, Nuevo León).
In western Texas and northern Mexico, Cylindropuntia kleiniae forms hybrids with C. leptocaulis (= C. ×antoniae P. V. Heath) that have varying degrees of morphologic intermediacy and chromosome number of 2n = 33. In northern Mexico, C. kleiniae hybridizes with C. imbricata var. imbricata. Cylindropuntia kleiniae itself may be of hybrid origin.