Plants branched, clumps to 20 × 100 cm. Stems weak, sprawling, soon decumbent [erect and rhizomatous], ± 10-60 × 1-2[-6] cm; ribs 4-5, crests sharp and straight to poorly defined and undulate; areoles 5-12 mm apart. Spines (3-)4-7(-9) per areole, usually very stiff and straight, yellowish, tan, ashy white to dark gray, or pale pink, tips dark, all terete; radial spines (3-)4-6(-8) per areole, spreading, 6-37 mm; central spines 0-1 per areole, porrect or ascending, 4-36(-60) mm. Flowers 6-10 × 7.5-10(-15) cm; flower tube 20-25 × 8-20 mm; flower tube hairs 3-6 mm; inner tepals brilliant pink or magenta distally with distinct white or yellow proximal regions of variable extent [very rarely white throughout], 3.5-6 × 9-18 mm, tips relatively thin and delicate; anthers orange-yellow; nectar chamber 3-6 mm. Fruits green, (10-)15-25 mm, pulp white. 2n = 22. Flowering Apr-May; fruiting 3-4 months after flowering. Tamaulipan thorn scrub, Agave lechuguilla-Hechtia associations, alluvial coastal plains, [pine-oak forests, limestone cliffs]; 0-2200 m; Tex.; Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas). Our northern plants of Echinocereus pentalophus are var. procumbens (Engelmann) P. Fournier; they have often been misidentified as E. berlandieri. Both taxa have often been misidentified as the Mexican species E. blanckii [often misspelled as E. 'blankii'], of confused authorship. Confusing variation of E. pentalophus has promulgated misidentifications, misapplications of names, and attempts to recognize multiple taxa.