Pisidium fallax Sterki, 1896
Sterki, 1896. Nautilus 10(2): 20.

Pisidium fallax — Herrington (1962), Mackie et al. (1980), Turgeon et al. (1998), Schultheiß et al. (2008), Bogan (2010), ITIS (2012), Clewing et al. (2013), Saito et al. (2022)
Pisidium (Cyclocalyx) fallax — Clarke (1973), Burch (1975), Bespalaya et al. (2017), Fuentealba-Jara et al. (2017)
Cyclocalyx fallax — Lee & Ó Foighil (2003)
Euglesa (Cyclocalyx) fallax — Mouthon & Forcellini (2017)
Euglesa (Casertiana) fallax — Bespalaya et al. (2023)

Pisidium fallax var. sepentrionale Sterki, 1898
Sterki, 1898. Nautilus 12(7): ??.
(intro'd as intra-sp. of Pisidium fallax Sterki, 1896; renamed Pisidium fallax var. boreale Sterki, 1899; renamed Pisidium fallax var. errans Sterki, 1905)

Pisidium (Cyclocalyx) fallax — Burch (1975)

Pisidium kirklandi Sterki, 1899
Sterki, 1899. Nautilus 13(1): ??.

Pisidium fallax — Herrington (1962)
Pisidium (Cyclocalyx) fallax — Burch (1975)

Pisidium fallax var. boreale Sterki, 1899
Sterki, 1899. Nautilus 13(1): ??.
(homonym of Pisidium boreale Westerlund, 1876; intro'd as intra-sp. of Pisidium fallax Sterki, 1896; new name for Pisidium fallax var. sepentrionale Sterki, 1898)

Pisidium (Cyclocalyx) fallax — Burch (1975)

Pisidium fallax var. errans Sterki, 1905
Sterki, 1905. Nautilus 19(7): ??.
(intro'd as intra-sp. of Pisidium fallax Sterki, 1896; new name for Pisidium fallax var. sepentrionale Sterki, 1898)

Pisidium (Cyclocalyx) fallax — Burch (1975)

Pisidium fallax var. mite Sterki, 1905
Sterki, 1905. Nautilus 19(7): ??.
(intro'd as intra-sp. of Pisidium fallax Sterki, 1896)

Pisidium (Cyclocalyx) fallax — Burch (1975)

Pisidium fallax pressum F.C. Baker, 1928
F.C. Baker, 1928. Bull. Wisconsin Geol. Nat. Hist. Survey 70(2): ??.
(intro'd as intra-sp. of Pisidium fallax Sterki, 1896)

Pisidium (Cyclocalyx) fallax — Burch (1975)