Calliopsis (Coreopsis tinctoria)
Also called Plains Coreopsis, and it is indeed native to the Great Plains. Its showy flowers, however, have made it welcome in gardens everywhere, and it often escapes where it finds an environment that reminds it of home. This patch was growing in a hillside clearing in Scott Township, where the soil had recently been disturbed. It was blooming in early July.
Gray describes the genus and the species:
COREOPSIS L. Tickseed
Heads many-flowered, radiate; rays mostly 8, neutral, rarely wanting. Involucre double; each series of about 8 bracts, the outer foliaceous and somewhat spreading; the inner broader and appressed, nearly membranaceous. Receptacle flat, with membranaceous chaff deciduous with the fruit. Achenes flat, obcompressed (i.e. flattened parallel with the bracts of the involucre), often winged, not narrowed at the top, 2-toothed or 2-awned, or sometimes naked at the summit; the awns not barbed downwardly. — Herbs, generally with opposite leaves and yellow or party-colored (rarely purple) rays. Too near the last section of Bidens, but generally well distinguished as a genus. (Name from koris, a bug, and opsis, appearance; from the form of the achene.)
§1. Style-tips truncate or nearly so; outer involucre small and short; rays rosecolor or yellow, with brown base; pappus an obscure border or none.
С tinctoria Nutt. Annual, glabrous, often 1 m. high; leaves 1-2-pinnately divided, the lobes lanceolate to linear; achenes oblong, wingless; rays yellow, with more or less of crimson-brown. — Minn, to Tex., etc.; common in cultivation; often escaping to roadsides, etc., eastw.