Synonyms: Binghamia australis; Binghamia decumbens (homotypic); Borzicactus decumbens (homotypic); Cereus decumbens (homotypic); Echinopsis decumbens (homotypic); Echinopsis magliana; Echinopsis subtilispina; Haageocereus ambiguus; Haageocereus ambiguus reductus; Haageocereus ambiguus var. reductus; Haageocereus aticensis; Haageocereus australis var. acinacispinus; Haageocereus chalaensis; Haageocereus decumbens f. spinosior; Haageocereus decumbens spinosior; Haageocereus decumbens var. brevispinus; Haageocereus decumbens var. spinosior; Haageocereus litoralis; Haageocereus mamillatus var. brevior; Haageocereus mammillatus; Haageocereus mammillatus brevior; Haageocereus oconacamanensis; Haageocereus subtilispinus