common pepper-grass —  Lepidium densiflorum elongatum {mustard family — Brassicaceae (Cruciferae)}
Flora of the Yukon Territory, Cody, p. 352c
check this { 1/250 sec, f7.1} – {airport, Whitehorse, Yukon} – {09/07/05 Saturday, July 9, 2005; 3:50:27 PM}