Type locality: Canada, Nunavut, Keewatin District, south end of Dubawnt Lake, Thomson 20416 (WIS - holotype).

Coordinates: 63°4'0"N, 101°42'0"W; 63.066667, -101.7.

Note: "It is probable that P. thomsonii is a good species, although the diagnosis given by Gowan is insufficient to fully characterize it and further work is requird to identify the critical differences that separate it from P. macrocarpa" (xxxx).

The Keewatin District is no longer part of the Northern Territories, but part of Nunavut, which was founded in 1999.