Annual herbs, robust, spiny; stems erect, branched, ribbed, terete. Leaves basal and cauline, alternate, toothed to pinnatisect, spiny. Capitula subglobose, terminal, in racemose clusters or solitary; involucral bracts in many series, leathery, unequal, with a spinose or acuminate apical appendage; receptacle flat, hairy. Florets bisexual, fertile, tubular, more or less equal; corolla deeply 5-lobed, glabrous; anthers sagittate at base, tailed, with acuminate appendages at apex; style bilobed, with appressed linear terete branches. Cypselas obliquely broad-obovoid, compressed, glabrous; pappus of several outer series of plumose bristles united in a ring at base (deciduous as a single unit), and an inner ring of short hairs united in a ring at base.
