371. Hymenothrix A. Gray, Mem. Amer. Acad. Arts, n. s. 4: 102. 1849.
[Greek hymen, membrane, and thrix, hair, possibly alluding to scarious-aristate pappus scales]
John L. Strother
Annuals, biennials, or perennials, 10–70[–150] cm. Stems erect, branched. Leaves basal and cauline; mostly alternate (proximal opposite); petiolate; blades 2-ternately [pinnately] lobed, ultimate margins entire, faces usually ± scabrellous (hairs white, antrorse, 0.1–0.5 mm), sometimes glabrate, sometimes gland-dotted. Heads radiate or discoid, in corymbiform to paniculiform arrays. Involucres obconic to hemispheric, 4–8+ mm diam. Phyllaries persistent, 8–16 in 2–3 series (reflexed in fruit, obovate or oblanceolate to linear, subequal, sometimes subtended by 1–3 bractlets, thin-herbaceous to membranous, margins scarious, often tinged with purple). Receptacles flat or convex, knobby or smooth, epaleate. Ray florets 0, or 3–8+, pistillate, fertile; corollas yellowish. Disc florets 10–30+, bisexual, fertile; corollas yellowish or whitish or pinkish to purplish (sparsely glandular-hairy), tubes about equaling cylindric throats or much longer than broadly funnelform throats, lobes 5, lance-oblong or lance-linear. Cypselae obpyramidal, 4–5-angled, faces ribbed and sparsely hairy (hairs straight); pappi persistent, of 12–18 narrowly lanceolate to subulate, medially thickened, scarious-margined scales in 1 series, some or all ± aristate. x = 12.
Species 5 (3 in the flora): sw United States, Mexico.
Turner, B. L. 1962. Taxonomy of Hymenothrix (Helenieae, Compositae). Brittonia 14: 101–120.