Chalk Hill Hymenopappus

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.

Hymenopappus tenuifolius Pursh, Fl. Am. Sept. 742. 1814
A leafy-stemmed biennial; stem 3-7 dm. high, corymlwsely branched above, loosely floccose; leaves 2-10 cm. long, twice pinnatifid into fihform divi-sions, loosely floccose; involucre hemispheric, 5 mm. high, 7-8 mm. broad; bracts obovate, with yellow tips, floccose;. corollas light-yellow; tube about 1.5 mm. long; throat fully 1 mm. long; lobes ovate, somewhat
shorter; anthers only partly exsertcd; achenes 3 mm. long, strongly striate, villous-hirsute
on the angles; squamcllac obovate, fully 1 mm. long.
Type locality: "Upper Louisiana" [probably South Dakota]. Distribution: North Dakota to Kansas, northern New Mexico, and Wyoming.

Hymenopappus tenuifolius, the Chalk Hill hymenopappus, is a North American species of flowering plant in the daisy family. It grows in the central and southeastern United States, primarily on the Great Plains from Texas and New Mexico north as far as South Dakota.

Hymenopappus tenuifolius is a biennial herb up to 150 cm (5 feet) tall. It produces 20-200 flower heads per stem, each head with 25–50 white disc flowers but no ray flowers.