Hymenopappus tenuifolius Pursh

Biennials, 40–150 cm. Leaves 2-pinnate, 8–15 cm, lobes (3–)5–15+ × 0.5–1.5+ mm; cauline 8–30. Heads 20–200 per stem. Pedun-cles 1–5 cm. Phyllaries yellowish, 5–8 × 2–4 mm. Ray florets 0. Disc florets 25–50; corollas whitish, 2.5–3 mm, tubes 1.5–2.2 mm, throats campanulate, 0.8–1.5 mm, lengths 1.5–2 times lobes. Cypselae 3.5–4.5 mm, ± villous; pappi of 16–18 scales 1–1.5(–2) mm. 2n = 34.