Biennials or perennials, to 120 cm. Stems erect, often scapiform (1 stem per crown in biennials, usually 3+ in perennials). Leaves mostly basal or basal and cauline; alternate; petiolate; blades usually 1–2+ times pinnately lobed (lobes usually ± filiform), ultimate margins usually entire, rarely toothed, faces glabrous or hairy, often tomentose, usually gland-dotted as well. Heads radiate or discoid, in ± corymbiform arrays. Involucres obconic to hemispheric, 4–15+ mm diam. Phyllaries 5–13+ in 2–3+ series, subequal, usually membranous- or scarious-margined (often yellowish, whitish, or purplish). Receptacles flat or convex, epaleate (except H. newberryi). Ray florets 0 or 8, pistillate, fertile; corollas white to ochroleucous. Disc florets 12–70+, bisexual, fertile; corollas usually yellow to ochroleucous or whitish to purplish, tubes longer than or about equaling funnelform or abruptly dilated, campanulate throats, lobes 5 (reflexed at anthesis). Cypselae obpyramidal (4-, sometimes 5-angled, each face usually 1–4-ribbed, glabrous or hirtellous to villous); pappi 0 or of 12–22 orbiculate to spatulate scales. x = 17.

Distribution

North America, Mexico.

Discussion

Species 11 (10 in the flora).

My treatment of Hymenopappus is essentially an adaptation of that by B. L. Turner (1956).

Selected References

Turner, B. L. 1956. A cytotaxonomic study of the genus Hymenopappus (Compositae). Rhodora 58: 163–186, 208–242, 259–269, 295–308.

Lower Taxa

Hymenopappus artemisiifolius, Hymenopappus biennis, Hymenopappus carrizoanus, Hymenopappus filifolius, Hymenopappus flavescens, Hymenopappus mexicanus, Hymenopappus newberryi, Hymenopappus radiatus, Hymenopappus scabiosaeus, Hymenopappus tenuifolius

Key

1	Perennials (usually 3+ aerial stems from crown); cauline leaves mostly 0–12; heads 1–20(–50) per stem; disc corolla throat lengths 2–8 times lobes	> 2
1	Biennials (usually 1 stem from crown); cauline leaves (2–)10–100; heads (15–)20–200 per stem; disc corolla throat lengths 1–2(–3) times lobes	> 5
2	Ray florets 8	> 3
2	Ray florets 0	> 4
3	Basal leaves 12–25 cm; peduncles 6–15 cm; pappi 0, or 0.01–0.1 mm (receptacles paleate)	Hymenopappus newberryi
3	Basal leaves 8–14 cm; peduncles 3–8 cm; pappi 0.4–0.6 mm	Hymenopappus radiatus
4	Leaf blades simple or 1-pinnate; cypselae glabrous or sparsely hirtellous	Hymenopappus mexicanus
4	Leaf blades 2-pinnate; cypselae hirtellous to villous	Hymenopappus filifolius
5	Ray florets 8	Hymenopappus biennis
5	Ray florets 0	> 6
6	Basal leaves simple or 1–2-pinnate, lobes (1–)5–30 mm wide; disc corollas whitish or purplish (not yellowish), tubes 2–3 mm	> 7
6	Basal leaves 2-pinnate, lobes 0.5–6 mm wide; disc corollas whitish or yellowish, tubes 1.5–2.2 mm	> 8
7	Basal leaves simple or 1-pinnate; disc corollas usually purplish, rarely whitish; pappi 0.3–2 mm	Hymenopappus artemisiifolius
7	Basal leaves 1–2-pinnate; disc corollas whitish; pappi 0.1–1 mm	Hymenopappus scabiosaeus
8	Lobes of basal leaves 1–6 mm wide; disc corollas yellowish; pappi 0.5–1.5 mm	Hymenopappus flavescens
8	Lobes of basal leaves 0.5–1.5 mm wide; disc corollas whitish; pappi 1–1.5(–2) mm	> 9
9	Disc corollas 3–4 mm, throats ± funnelform	Hymenopappus carrizoanus
9	Disc corollas 2.5–3 mm, throats ± campanulate	Hymenopappus tenuifolius