I suppose if one wanted to be pedantic, this would be the only species one could call a calla lily (though it’s not a lily), as Calla palustris is the sole member of its genus. What many English-speaking people generally call calla lilies are members of the related genus, Zantedeschia. To be fair, though, species now named Zantedeschia were (all?) formerly in Calla.
The first photograph was taken in eastern Ontario in early June, ten days prior to the other two images from central British Columbia. This hints at a broad geographic range for bog arum / water arum / wild calla / marsh calla–and that is indeed the case. Calla palustris is native to cool temperate areas of the northern hemisphere. Its North American range nearly overlaps the expanse of taiga in North America, so one could draw the same conclusion about its presence in Eurasia roughly paralleling the Eurasian extent of taiga. This is almost the case, though notably it can also be found in central Europe as far southwest as France.
The Plants for a Future database provides information on the economic botany of the species (Calla palustris), including its use as a food (with appropriate cautions).
The epithet palustris refers to the preferred habitat: “of marshes” or “of swamps”.
Agriculture resource links: A critical component of global food security is to preserve the various strains of heritage fruits and vegetables. Certain hybrids may be more resistant to particular diseases, others may be more adapted to local climates and others may have the highest nutritional value (as examples of reasons why). I’ve received a number of emails today about the potential destruction of the Pavlovsk Experimental Station, which has “5,500 different varieties of apples, pears, cherries, and numerous berry species — most of which occur nowhere else on Earth and were developed over hundreds of years by farmers in northern Europe, Scandinavia and Russia” (quoted from The Scientist, read more: “Critical plant bank in danger“). Nature.com is also reporting on the story, “Europe’s largest berry bank faces closure“. The Global Crop Diversity Trust is working to prevent the destruction of the station and its crop diversity (if you intend to sign their petition and do not reside in the USA, use this one instead of the one in the middle of the Global Crop Diversity Trust page (which seems to assume one resides in the USA)).