Perennial herbs with short to long rhizomes; stems erect, terete to slightly ribbed, usually with short simple hairs in lines or stripes above and glabrous below, sometimes completely glabrous, branched only above, (15)-40-150 cm tall. Mid cauline lvs elliptic, oblong, or ovate- to narrow-lanceolate, narrowed or broad at base and slightly auriculate to amplexicaul, entire, or serrulate to coarsely serrate, usually glabrous, sometimes sparsely hairy about margins, 50-100-(170) × 10-30 mm; uppermost lvs smaller, sometimes cuneate, sometimes ± triangular and broad-based. Infl. a few- to many-headed narrow panicle or ± flat-topped cyme. Capitula 25-50 mm diam.; peduncles usually with lines or stripes of simple hairs, sometimes glabrous. Involucral bracts ± equal to very unequal; inner bracts oblong- to linear-lanceolate, acute to acuminate, glabrous, with a diamond-shaped to diffuse green patch near apex and extending down midrib, also sometimes tinged purple, 5-8 mm long; outer bracts green at tip to wholly herbaceous, erect to spreading, and from 2 mm long to = inner bracts. Ray florets numerous; ligules usually violet to blue, rarely white, 7-14 mm long. Ovary with scattered antrorse hairs; mature achenes not seen.