1. Heterotheca camporum (Greene) Shinners

Chrysopsis camporum Greene

C. villosa (Pursh) Nutt. ex DC. var. camporum (Greene) Cronquist

Pl. 236 a, b; Map 986

Plants perennial herbs, with stout taproots and rhizomes, the rootstock often somewhat woody. Stems 40–140 cm long, slender to more commonly relatively stout, moderately pubescent (especially toward the tip) with a mixture of minute, appressed or curved, slender-based hairs and longer, spreading hairs with expanded, bulbous, pustular bases, also with moderate to dense, minute, sessile or slightly stalked glands. Stem leaves (1–)3–7 cm long, linear to narrowly oblanceolate or oblanceolate, mostly short-tapered to a sharply pointed-tip, the margins entire or with few to less commonly several fine, sharp teeth, hairy with at least some of the hairs relatively long, stout, and spreading, the surfaces appearing green or rarely slightly grayish-tinged, moderately roughened with loosely appressed to somewhat curved or spreading hairs, these all or mostly with an expanded, bulbous base, not glandular or rarely with sparse to moderate, minute, sessile to slightly stalked glands. Involucre 7–10 mm long, the bracts in 3–6 unequal, overlapping series, narrowly lanceolate to nearly linear, sometimes purplish-tinged at the tip, the green central stripe usually easily observed, not hidden by the sparse to moderate, short, curved hairs, not glandular or sparsely to moderately glandular. Ray florets 15–35, the corollas 11–15 mm long. Disc florets 25–65, the corollas 5.0–6.5 mm long, glabrous or occasionally very sparsely and minutely hairy on the outer surface toward the tip. Pappus of the ray and disc florets similar, consisting of an outer series of several bristlelike scales 0.2–1.0 mm long and an inner series of 25–45 bristles 5–7 mm long. Fruits of the ray and disc florets similar, 1.5–4.0 mm long, somewhat flattened, 3- or 4-nerved on each face, the surface moderately hairy. 2n=36. July–October.

Scattered mostly south of the Missouri River (Virginia to North Carolina west to Illinois, Missouri, Arkansas, and Mississippi). Sand prairies, glades, ledges and tops of bluffs, openings of dry upland forests, banks of streams and rivers, bottomland forests, and swamps; also pastures, old fields, fallow fields, levees, railroads, roadsides, and open, disturbed areas, often in sandy soils.

Steyermark (1963) and most earlier authors treated this taxon as a variety of H. villosa, but most recent authors (Gleason and Cronquist, 1991; Semple, 1996) have followed Harms (1963, 1968) in accepting it as a separate species. In a fascinating study, Semple (1983) detailed the apparent differentiation of the species into two varieties toward the beginning of the twentieth century (see further discussion below), both of which occur in Missouri.