Plants unbranched or few branched (rarely forming clumps of 12+ branches). Stems erect, spheric to short cylindric, (3-)8-30(-35) × 2.8-9 cm; ribs 10-20, crests prominent, slightly to conspicuously undulate; areoles 3-12 mm apart. Spines (13-)18-30(-55) per areole, stiff (flexible) and straight (or slightly curved), sometimes pectinately arranged, red-and-white, red-and-yellow, yellow-and-white, whitish, yellowish, or purplish, tips often darker; radial spines 12-38(-45) per areole, appressed to spreading, (2-)4-18 mm; central spines 0-17 per areole, spreading to projecting, terete (subulate), 3-5-40 mm. Flowers 2-3.5 × (1-)1.5-3 cm; flower tube (4-)5-12 × 5-15 mm; flower tube hairs 1-2 mm; inner tepals shades of yellow or brown, frequently tending towards yellowish green or brick red (rarely carmine in Davis Mountains populations), often with darker purplish maroon midstripes, 10-25 × 2-4 mm, tips relatively thin and delicate; anthers yellow; nectar chamber 1-2[-3] mm. Fruits yellowish green to dark green, dark purple, or reddish tinged, 6-17 mm, pulp white. 2n = 22.
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