The one or two light to dark brown central spines are directed downwards and are up to 5 cm (2.0 in) long.

The up to 30 and more needle-like yellowish radial spines have a length of 5 to 8 mm (0.20 to 0.31 in).

[3] Haageocereus decumbens is distributed in Peru in the Arequipa region near Chala and Mollendo at altitudes of 200 to 700 meters.

The first description as Cereus decumbens was made in 1913 by Friedrich Karl Johann Vaupel.

(1937, incorrect name ICBN article 11.4) and Echinopsis decumbens (Vaupel) Mayta (2015).