Echinocereus poselgeri Lem.

Body scrambling, cylindric to 60 cm high, 1-2 cm wide with 8-10 low ribs. Areoles with 9-17 radial spines to 9 mm long. Flowers pink, 7 cm wide. [Wilcoxia poselgeri (Lem.) Britton & Rose]

NE Mexico, SW North America

Source: Forbes, S. (1997). Echinocereus. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Caryophyllanae
order      Caryophyllales
family       Cactaceae
genus        Echinocereus Engelm.