Cact.-Verz., 19. 1859.
Plants branched, sprawling, clones to 3 m or more wide. Stems soon decumbent, cylindric, (10–) 20–36 × 1.5–3 cm; ribs 5–7, crests undulate; areoles 10–15 mm apart. Spines 9–10 per areole, straight, stiff, white, tipped dark; radial spines 6–9 per areole, appressed-spreading, to 10 mm; central spines 1–3 per areole, projecting outward, to 30 mm. Flowers 5–6 × 0.2–4.8 cm; flower tube 10–20 × 10–30 mm; flower tube hairs short, inconspicuous; inner tepals purplish-pink or magenta, often with darker midstripes and/or proximal region, 40 × 18 mm, tips relatively thin and delicate; anthers yellow; nectar chamber 4–6 mm. Fruits olive green to 25 mm, pulp white or colorless. 2n = 22.
Phenology: Flowering May–Jun; fruiting 2-3 months after flowering.
Habitat: Shady thickets, coastal plain
Elevation: 0-100[-600] m
Tex., Mexico (Tamaulipas)
Echinocereus berlandieri was originally discovered along the Nueces River, presumably the mouth of the river near Corpus Christi, and has not been seen there since. It has been rarely documented also from the lower Rio Grande Valley. Published records from elsewhere are all based on misidentified material of E. pentalophus, E. papillosus, E. enneacanthus var. brevispinus, and (in Mexico) E. cinerascens (de Candolle) Haage var. tulensis (Bravo) N. P. Taylor. Like E. pentalophus from the same region, E. berlandieri has often been misidentified as E. blanckii (Poselger) Palmer, a Mexican species. Furthermore, D. Weniger (1970) misapplied the name E. berlandieri to part of the common and variable E. pentalophus.
"thin" is not a number.