Regarding the 2018 rediscovery of Opuntia polyacantha Haw., in Ontario, Canada:
Opuntia polyacantha Haw. (Cactaceae) was previously excluded from the "Atlas of the Rare Vascular Plants of Ontario" as an unconfirmed species.
Argus, G.W., C.J. Keddy, K.M. Pryor and D.J. White. 1982-1987. Atlas of the Rare Vascular Plants of Ontario, G.W. Argus & D.J. White (eds.). National Museum of
Natural Sciences, Botany Division, Ottawa, Ont.
"Excluded species of Cactaceae / Espèces de Cactaceae exclues
J/SI - unconfirmed/situation incertaine
USI Opuntia polyacantha Haw."
