Basionym: The name on which a new combination or name at new rank is based. It provides the final epithet of the new combination or name at new rank.
Echinocereus pentalophus is based on the basionym Cereus pentalophus (the species was originally assigned to the genus Cereus and later transferred to Echinocereus).
Echinocereus ferreiranus subsp. lindsayi is based on the basionym Echinocereus lindsayi (it was originally published as separate species in the genus Echinocereus and later reclassified as a subspecies of the species Echinocereus ferreiranus).