Rough rattlesnake-root is an erect forb, 5-17dm tall, with a narrow and elongate inflorescence with a raceme-like or a dense panicle. Heads are crowded, loosely ascending to suberect, with 8-19 (usually 11-14) ochre-colored flowers, and a straw-like pappus. It has a strict stem that is rough-hairy. Its fruit are elongate, smooth, mostly reddish-brown achenes. Leaves are alternate, rough or coarsely covered with short, stiff hairs beneath and often also on the upper side, they are toothed or entire. Lower leaves are well developed and somewhat obovate, and taper to the petiole, and soon deciduous. Upper leaves are sessile or nearly so and often clasping, oblong to elliptic or lanceolate, gradually reduced upward, the larger ones are 4-11cm long by 1-5cm wide.