Inflorescences: involucral bracts with base cordate or reniform, rarely subtruncate; terminal leaflets light green, margins proximally mostly straight to convex-sided, variously lobed or serrate, variously pubescent. Flowers: sepals (6-)10-20 mm, abaxially usually thinly pubescent; anthers (0.9-)1-1.7 mm. Heads of achenes ovoid to ovoid-cylindric, (9-)11-14 mm diam. 2 n =16.

Flowering summer (Jun-Aug). Dry, rocky, open woods, thickets, river banks; 0-2000 m; Ont., Que.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Vt., Va., W.Va., Wis., Wyo.