1b. var. flavus

T. flavus f. cupreus (Jacq.) Fosberg

Inflorescences usually somewhat arched or drooping, the branches somewhat arched or drooping, their bases thickened only on 1 side, glabrous or with a tuft of very short hairs on the thickened side. Spikelets with the stalks 1–5 mm long, mostly appressed to the inflorescence branches. 2n=40. July–September.

Common throughout the state (eastern U.S. and adjacent Canada west to Illinois, Nebraska, and Texas). Upland prairies, glades, savannas, openings of mesic to dry upland forests and bottomland forests, and margins of streams; also roadsides, railroads, ditches, old fields, and open, disturbed areas.

This taxon spreads quickly into disturbed areas and is quite common along roadsides in the state.