Plants 100-300 cm. Stems ridged to angulate (usually glabrous, rarely sparsely puberulent distally, not glaucous). Basal leaves: (petioles to 30 cm) blades (with 3-5 main veins) reniform or ovate-cordate, to 40+ cm, margins lobed or dentate. Cauline leaves: proximal petiolate, blades ovate, margins entire, serrate, or dentate; distal petiolate or sessile, smaller (rarely hairy). Involucres (8-)10-13(-14) mm. Phyllaries pale green, narrowly ovate, midveins not winged (tips obtuse). Corollas white or greenish, 8-9(-10.5) mm. Cypselae fusiform or clavate, 4-5 mm (dark brown or purple, 4-5-ribbed); pappi 6-8 mm. 2n = 50. Flowering mid May-early Sep. Open woods; 10-500 m; Ala., Ark., Del., Ga., Ill., Ind., Iowa, Ky., Md., Minn., Miss., Mo., N.J., N.C., Ohio, Okla., Pa., Tenn., Va., W.Va., Wis. Arnoglossum muehlenbergii of H. Robinson, Cacalia muhlenbergii of Fernald, and Mesadenia muhlenbergii of Rydberg were based on Senecio muehlenbergii Schultz-Bipontinus, a superfluous name based on Cacalia reniformis Muhlenberg ex Willdenow.