common mare's-tail —  Hippuris vulgaris {mare's-tail family — Hippuridaceae}
Flora of the Yukon Territory, Cody, p. 447a
 { 1/30 sec, f18.0} – {McIntyre Ck. college, Whitehorse, Yukon} – {12/08/09 Wednesday, August 12, 2009; 3:22:23 PM}