Annual or perennial herbs. Leaves linear to ovate, simple; margin entire or ± dentate. Capitula heterogamous, radiate; ray florets female, in 1 series, often blue or violet; disk florets tubular, bisexual, yellow, their lobes spreading, sometimes with red margins. Phyllaries 3-4-seriate, imbricate; outer much shorter than inner. Achenes oblong, flattened, ± hairy and always glandular. Pappus hairs scabrid, whitish to yellowish, in 2, sometimes indistinct, rows.