Slag Plateaus Areas of slag with little humus (decomposing plant material or topsoil) and only scattered grasses and pioneer species. Photo by Bob Bingham   Foxtail barley (Hordeum jubatum), a native plant found along roads and in waste areas, grows well in the open slag areas of Nine Mile Run.     Several small plants of dwarf snapdragon (Chaenorrhinum minus) were collected in an area of open slag. Illustration from Newcomb's Wildflower Guide, illustrated by Gordon Morrison.