Proc. Amer. Acad. Arts 17: 220. 1882.
Subshrubs or shrubs, 40–80(–150+) cm (usually with tufts of hairs in axils of leaves). Leaves cauline; sessile; blades linear, bases cuneate, margins entire or proximally spiny, faces tomentulose, glabrescent. Heads discoid, clustered in second-order heads (each cluster 15–25 mm diam. and subtended by ovate to orbiculate, prickly-margined bracts). Involucres (each enclosing 1 floret) cylindric to fusiform, 10 mm. Phyllaries in 2–3 series, ovate to lanceolate or linear, unequal, apices acute to cuspidate. Receptacles flat, smooth, glabrous, epaleate. Florets 1, bisexual, fertile; corollas reddish purple to greenish white, actinomorphic (lobes 5, lance-linear, glabrous); anther basal appendages slightly fimbriate, apical appendages lanceolate, acute; style branches relatively stout (0.1–0.5 mm), apices rounded (abaxial faces papillose to pilose). Cypselae ± terete (± 4 mm), not beaked, obscurely 4–5-nerved, faces glabrescent, not glandular-hairy; pappi of 6 unequal, lanceolate or multitoothed scales (sometimes ± coalescent and forming lacerate crowns). x = 8.
sw United States.