What is a low irregular shrub (Artemisia tridentata), of the order Compositæ, covering vast tracts of the dry alkaline regions of the American plains; -- called also sagebush, and wild sage called?

sagebrush — A low irregular shrub (Artemisia tridentata), of the order Compositæ, covering vast tracts of the dry alkaline regions of the American plains; -- called also sagebush, and wild sage. (Webster's 1913.)