Publication: Succulenta (Netherlands). 71: 99. 1992.
selected vouchers: WTU
Notes: Pediocactus simpsonii var. robustior is the name H&C applies to the taxon found in Washington. FNA Volume 4 treats this taxon as not occurring in Washington, therefore the name P. simpsonii var. robustior is considered misapplied to plants in Washington.