351. Hymenopappus L’Héritier, Hymenopappus. plate. 1788.
[Greek hymen, membrane, and pappos, pappus, alluding to membranous pappus scales]
John L. Strother
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.
Species 11 (10 in the flora): North America, Mexico.
My treatment of Hymenopappus is essentially an adaptation of that by B. L. Turner (1956).
Turner, B. L. 1956. A cytotaxonomic study of the genus Hymenopappus (Compositae). Rhodora 58: 163–186, 208–242, 259–269, 295–308.