1. Pluchea camphorata (L.) DC. (stinkweed, camphor weed, inland marsh fleabane)

Pl. 295 g–i; Map 1244

Plants annual or short-lived perennial. Stems 40–100(–200) cm long, minutely hairy, sometimes nearly glabrous toward the base, occasionally also with sparse, longer hairs. Leaves short-petiolate or, if sessile, then not clasping the stem. Leaf blades 4–15 cm long, lanceolate to ovate or elliptic, angled or tapered at the base, angled or tapered to a sharply pointed tip, the margins with widely spaced teeth or more or less scalloped, rarely nearly entire, both surfaces with sparse to moderate, sessile, spherical glands, the undersurface also minutely hairy. Inflorescences of relatively dense clusters at the branch tips, these sometimes paniculate, appearing flat-topped or more commonly rounded in profile. Heads 5–9 mm in diameter. Involucre 4–6 mm long, the outer bracts triangular-ovate, grading to the inner, oblong-lanceolate bracts, angled to tapered at the tip, papery and white to tan, often pinkish- or purplish-tinged, at least toward the tip, the outer surface with sessile, spherical glands and often also minute hairs, rarely nearly glabrous. Corollas 3–6 mm long, pink to pinkish purple. Pappus bristles 3–5 mm long, white or pinkish-tinged. 2n=20. August–October.

Scattered in the southern quarter of the state north disjunctly to St. Louis County; apparently introduced in Jackson County (Pennsylvania to Florida west to Kansas and Texas). Bottomland forests, swamps, sloughs, banks of streams and rivers, margins of lakes, ponds, and sinkhole ponds, bottomland prairies, and marshes; also ditches and roadsides.