This rhizomatous species is centered in the lower Mississippi Valley (K) and reaches its northern limits in or near s. Mo (F), nw. Tenn. (Ch) and w. Ky. The only confirmed Ky. records are colls. of R. Athey and KSNPC from Fish Pond and Reelfoot Lake in FULT (KY, EKY). There has been confusion with graminea and rigida; records from MCRA (KY-Agr.) and especially JEFF (BT) are dubious and should be rechecked.