John Burton Cleland described Cortinarius subarcheri in 1928 from a collection under brown stringybark (Eucalyptus baxteri) in Bundaleer State Forest in the Mount Lofty Ranges. He distinguished it from C. archeri by its smaller spores (9-10 x 4.5-5.5 μm) and mushrooms. This taxon is poorly known and it is unclear whether it is distinct from C. archeri.