Thelesperma megapotamicum (Spreng.) Kuntze
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Of the Great Plains, has been reported as adventive in Ill. and Mo. It is a glabrous perennial with the lvs once or twice pinnatifid into slender segments; the discoid (or inconspicuously radiate) heads terminate long, naked peduncles; the outer invol bracts are very short, and the inner ones are connate to the middle or above; the wingless achenes have a pappus of 2 retrorsely barbed awn-scales. (T. gracile)