Subspecies, varieties, forms and cultivars of plants belonging to the Pterocactus tuberosus group

• Pterocactus kuntzei K.Schum.: not easily distinguishable from the other P. tuberosus, but usually with thinner and darker stems.
• Pterocactus tuberosus (Pfeiff.) Britton & Rose: is a geophyte cactus with huge tuberous roots under the soil ,with thin fragile blue-light to brownish-purple stems that breaks off easily.
• Pterocactus tuberosus var. decipiens (Gürke) W.T.Marshall
• Pterocactus tuberosus f. lelongii (Ruíz Leal ex R.Kiesling) R.Kiesling