Annuals or perennials, 20–80 cm. Stems 1–several, much-branched throughout, puberulent and ± gray tomentose. Leaves hispidulous and ± short-tomentose; basal and proximal cauline petiolate, often absent at anthesis, blades 10–20 cm, margins bipinnately dissected into narrow lobes; mid cauline sessile, bipinnately dissected; distal much smaller, entire or pinnately lobed. Heads disciform, in open paniculiform arrays. Involucres narrowly ovoid or cylindric, 10–13 × 3–5 mm. Principal phyllaries: bodies pale green, ovate to lanceolate, glabrous or finely tomentose, with a few prominent parallel veins, margins and erect appendages fringed with slender stramineous spines, each phyllary tipped by spine 1–3 mm. Inner phyllaries lanceolate, ± acute, appendage lacerate or spine-tipped. Florets 25–35; corollas cream white (rarely pink or pale purple), those of sterile florets 12–13 mm, slender, inconspicuous, those of fertile florets 12–13 mm. Cypselae dark brown, ca. 2–3 mm; pappi 0 or less than 0.5 mm, only rudimentary. 2n = 18, 36.
