Stalked Bur Grass, Tragus racemosus

Last summer while botanizing a railroad in Porter County, Indiana I noticed a dense, reddish colony of a short grass that from a distance looked like Stink Grass (Eragrostis megastachya or E. cilianensis).

Drawing closer I was startled to see uncinate spines on the indurated glumes and/or lemmas. It's difficult to tell what's a glume and what's a lemma on this unusual grass.

It turns out to be a little weed of limited distribution called Stalked Bur Grass, Tragus racemosus. According to literature, it catches in lambs' wool and shows up around woolen mills but does not persist.

Further exploration revealed two more colonies along this same track in neighboring Lake County, Indiana. This little grass certainly is not native here, but it's new and that makes it interesting, at least to me! Specimens are being deposited at the herbarium of the Morton Arboretum in Lisle, Illinois.