water smartweed —  Polygonum amphibium laevimarginatum {buckwheat family — Polygonaceae}
Flora of the Yukon Territory, Cody, p. 246a
 { 1/80 sec, f5.0} – {Paddys Pond/Ice Lake, Whitehorse, Yukon} – {13/08/06 Sunday, August 13, 2006; 4:37:06 PM}