Thelocactus knuthianus (Boed.) Borg, Cacti, ed. 1: 284. 1937 Thelocactus knuthianus (Boed.) Borg, Cacti, ed. 1: 284. 1937is new combination for Echinocactus knuthianus Boed. in Monatsschr. Deutsch. Kakteen-Ges. 2: 139. 1930Taxon for this nameThelocactus knuthianus (Boed.) Borg