common duckweed —  Lemna minor {duckweed family — Lemnaceae}
Flora of the Yukon Territory, Cody, p. 184a
 { 1/1000 sec, f5.6} – {McIntyre Ck. college, Whitehorse, Yukon} – {13/08/09 Thursday, August 13, 2009; 3:26:44 PM}