Xanthoparmelia chlorochroa  Xanthoparmelia chlorochroa, known as the tumbleweed shield lichen or ground lichen, is a foliose lichen in the Parmeliaceae family. It is not fixed to a substrate, and blows around in the wind from location to location. This lichen is abundant on the High Plains of Wyoming. Tumbleweed shield lichen is used as a dye by Navajo rug weavers. It has been used as a remedy for impetigo by the Navajo. It was implicated in the poisoning of domestic sheep and cattle in Wyoming during the 1930s. It has also been implicated in the poisoning of elk in 2004.