This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Prenanthes aspera, Michx. (Nabalus asper, T. & G.)
Native. Perennial. Propagates by seed.
Time of bloom: August to September.
Seed-time: September to October.
Range: Ohio to South Dakota, southward to Kentucky, Kansas, and Louisiana.
Habitat: Dry prairies; fields, pastures, waste places.
Grazing cattle usually leave this weed undisturbed to perfect its fruit, liking neither its rough-hairy foliage nor its bitter juices. Stem stout, simple, ridged, and bristly-hairy, two to four feet tall. Leaves long-oval or broadly lance-shaped, rather thick and firm, rough on both sides, sparsely toothed, obtuse, the basal ones tapering to winged petioles; those on the stem all sessile, the lower ones clasping and obtuse, the uppermost usually entire and acute. Heads numerous, in a long, spike-like panicle, mostly erect on very short pedicels, each about a half-inch broad, with twelve to fifteen cream-colored florets; involucre cylindric, very hairy, its principal bracts nearly a half-inch long, linear, with a few short, pointed, spreading ones at base. Achenes oblong, with straw-colored pappus.
Means of control should be the same as for Prenanthes serpentaria.