17. Heterotheca camporum (Greene) Shinners, Field & Lab. 19: 71. 1951.
Chrysopsis camporum Greene, Pittonia 3: 88. 1896; C. villosa (Pursh) Nuttall ex de Candolle var. camporum (Greene) Cronquist; Heterotheca villosa (Pursh) Shinners var. camporum (Greene) Wunderlin
Perennials, 35–110(–150) cm; taprooted, spreading by rhizomes. Stems 1–30(–100), ascending to erect (sometimes reddish brown, sometimes ± brittle), appressed-strigose, sparsely to moderately long-hirsute, eglandular or sparsely to moderately stipitate-glandular, more densely so distally; axillary fascicles absent. Leaves: proximal cauline subpetiolate to sessile, blades oblanceolate, 38–73 cm × 6–15(–18) mm, bases cuneate, margins flat, sparsely serrate, strigoso-ciliate, with a few long cilia proximally, faces moderately long-strigose, eglandular or sparsely to moderately stipitate-glandular; distal sessile (usually spreading, sometimes perpendicular), blades usually narrowly to broadly oblanceolate, rarely obovate or ovate, little reduced distally (not stiff), margins sparsely serrate (not long-ciliate), faces moderately strigose, sparsely to moderately stipitate-glandular. Heads (1–)5–24, usually in open to congested corymbiform arrays, sometimes borne singly, on long peduncular branches. Peduncles 5–35 mm, short-hispido-strigose, sometimes stipitate-glandular; bracts 1–3, proximal leaflike, becoming linear-lanceolate, less hairy and more stipitate-glandular distally, larger bracts subtending heads absent or very rare. Involucres cylindric to campanulo-hemispheric, 7–9(–10.5) mm. Phyllaries in 4–5 series, outer and mid narrowly triangular, unequal, margins hyaline, fimbriate-ciliate apically, faces sparsely strigose, eglandular or sparsely to moderately stipitate-glandular. Ray florets 16–29(–38); laminae 10.5–17(–21.5) × 1–2(–2.6) mm. Disc florets (23–)32–66; corolla barely ampliate, 5–6.6 mm, glabrous, lobes 0.5–1 mm, glabrous or glabrate. Cypselae monomorphic, compressed obconic, 1.7–3.9 mm, ribs 7–10 (often brownish), faces moderately strigose; pappi off-white, outer of linear scales 0.2–1 mm, inner of bristles 5–7 mm, longest weakly clavate.
Varieties 2 (2 in the flora): e United States.
Chance introductions (usually emphemeral) of Heterotheca camporum have occurred in Michigan, New Jersey, and likely other eastern states. Heterotheca camporum has well-developed serrations along the margins of its distal cauline leaves, which no other species has, although basal leaves in some species may have one or two serrations distally.