Coefficient of Conservatism:
Coefficient of Wetness:
A variable Eurasian species, often cultivated. O. A. Farwell (836, BLH) collected the white-flowered form in Keweenaw Co. in 1894 as “Sparingly escaped around gardens” (according to his notes).
The western P. occidentale Greene occurs disjunctly (as the rare Great Lakes region endemic subsp. lacustre Wherry) in Wisconsin, close to the western Upper Peninsula, and should be sought in conifer swamps.