17. Cylindropuntia munzii (C. B. Wolf) Backeberg, Kakteenlexikon. 113. 1966 (as hybrid).
Opuntia munzii C. B. Wolf, Occas. Pap. Rancho Santa Ana Bot. Gard. 2: 79, fig. 23. 1938
Trees or treelike shrubs, with trunk(s) and main branches spreading, bearing terminal tufts of usually drooping branchlets, 2-4 m. Stem segments easily detached, gray-green, 4-16 × 1.2-2.5 cm; tubercles prominent, narrowly oval, 1-2 cm; areoles subcircular to obdeltate, 5-7 × 3-4.5 mm; wool tawny to yellow-brown, aging gray. Spines (7-)9-14 per areole, at most areoles, erect or spreading, yellow, aging red- to gray-black with pale tips, terete or abaxial ones slightly flattened, the longest to 3 cm; marginal bristlelike spines shorter, 0-4; sheaths pale yellow becoming golden apically, baggy. Glochids in adaxial crescent and sometimes small tuft, yellow, inconspicuous, 0.5-2 mm. Flowers: inner tepals pale reddish maroon-brown, elliptic, of irregular lengths, 8-15 mm, emarginate-apiculate; filaments green; anthers yellow; style and stigma lobes cream. Fruits easily detached, tan when mature and fertile, globose, 17-24 × 17-21 mm, dry, tuberculate, spineless but bearing numerous very long glochids; basal tubercles not markedly longer than distal ones (except in sterile fruits); areoles 30-40. Seeds pale yellow, rounded-deltoid, slightly flattened, 3-4.5 × 3-4 mm, sides smooth; girdle smooth, not protruding. 2n = 22, 33.
Flowering spring (Mar-May). Sonoran Desert, flats, hills, sandy to rocky soils; 400-700 m; Calif.; Mexico (Baja California).
Cylindropuntia munzii hybridizes with C. echinocarpa forming a shrub to 1.5 m, with shorter tubercles and baggy-sheathed spines obscuring the stem and bearing fruits with long glochids but no spines. The chromosome number for the hybrid is 2n = 22.