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CommentsThis is the most common Aristida sp. (Three-Awn grass) in Illinois. Some of the less common Three-Awn grasses in the state are often found in dry sand prairies. The most striking feature of these grasses are the bent awns of their fertile lemmas. Prairie Three-Awn differs from many other Three-Awn grasses by the long awns of its fertile lemmas (at least 1" long). Other Three-Awn grasses have awns up to ¾" long (in some species, this applies only to their lateral awns, which are shorter than the central awns). An exception is Aristida tuberculosa (Needle Grass), which has awns on its lemmas that are about as long as those of Prairie Three-Awn. However, the awns of Needle Grass coil tightly around each other to form a basal column about ½" long, after which they bend away from each other in the manner of other Three-Awn grasses. The awns of Prairie Three-Awn and other Three-Awn grasses are free to the base, or they coil around each other to form a short basal column that is only 1/8" long.