Perennials, 5-10 cm. Leaves: basal 2-pinnate, 3-20 cm, lobes 2-50 × 0.5-2(-3) mm; cauline 0-12. Heads 1-60 per stem. Peduncles 1-16 cm. Phyllaries whitish to yellowish, 3-14 × 2-5 mm. Ray florets 0. Disc florets 10-80; cor-ollas usually yellowish, sometimes whitish, 2.2-7 mm, tubes 1-2.5 mm, throats campanulate, 1-3 mm, lengths 2-8 times lobes. Cypselae 3-7 mm, ± hirtellous to villous; pappi of 12-22 scales 0.1-3 mm.
Some plants are morphologically intermediate between some pairs of varieties of Hymenopappus filifolius as treated by B. L. Turner (1956).
FNA 2006, Kearney and Peebles 1969, McDougall 1973, Heil et al 2013
Duration: Perennial Nativity: Native Lifeform: Subshrub General: Perennial herbs to low subshrubs, to 100 cm tall, from a branching woody caudex; stems usually several per caudex, erect, usually densely whitish tomentose near the base. Leaves: Mostly basal, arising directly from the woody caudex, with up to 12 smaller leaves alternate on the stems; blades 3-20 cm long, once or twice pinnately dissected, the lobes linear, threadlike, minutely gland-dotted; leaves often whitish tomentose, especially near the leaf base and along center rib. Flowers: Flower heads discoid, yellow, on slender peduncles and usually arranged in corymbiform arrays at the tips of long scapes; involucres turbinate to campanulate, 4-12 mm high, the bracts (phyllaries) oblanceolate, 2-5 mm wide, usually somewhat hairy, green with membranous tips that can be tinged with yellow, white, or pink; florets all discs, 10-80 per flower head, yellow. Fruits: Achenes 4 angled, 3-7 mm long, densely short-hairy; topped with a pappus of 12-22 linear-oblong scales. Ecology: Found on limestone substrates from 3,000-10,000 ft (914-3048 m). Distribution: Alberta and Saskatchewan, south to WA, CA, and TX Notes: The mostly basal, pinnately lobed leaves; densely tomentose herbage; and yellow, curling corollas of the discoid heads help identify this species. Though younger plants may occasionally have a single flowering stem arising from a small caudex, this plant normally has several stems arising from a branched caudex and is undisputedly perennial. H. frondosus, though appearing similar, is a taprooted biennial with a single stout stem per plant, which may branch aboveground. H. frondosus also has more stem leaves (10 or more) while H. filifolius has 12 or fewer leaves per stem. Ethnobotany: A poultice of the root was applied to ease swellings, and a decoction of the root was taken as an emetic. The root was also used as a chewing gum, and the leaves were boiled and baked into bread. Etymology: Hymenopappus comes from Greek hymen for membrane and pappos for pappus, for the chafflike pappus scales; filifolius means thread like leaves. Synonyms: None Editor: LCrumbacher 2011, AHazelton 2017