Annuals or perennials, 40-100 cm; fibrous-rooted, sometimes rhizomatous. Stems (often dark purplish) arachnose, glandular. Leaves sessile; blades (thick, reticulate-veined) oblong to elliptic, lance-ovate, or ovate, mostly 3-10(-13) × 1-4 cm (bases clasping), margins denticulate (apices rounded to acute), faces minutely sessile-glandular. Heads in loose to dense, corymbiform arrays. Involucres usually cupulate to campanulate, sometimes turbinate-campanulate, 5-10 × 6-9(-12) mm (bases mostly rounded to impressed, sometimes obtuse). Phyllaries usually creamy white, sometimes cream, greenish, pinkish, rose-purplish, purplish, yellowish, or pale pink, thinly arachnoid-pubescent and sessile-glandular (the outer ovate to ovate-lanceolate, lengths mostly 0.2-0.6 times inner). Corollas creamy white to yellowish or pale pink. Pappi persistent, bristles distinct. Late Jul-Oct (year-round in south). Seasonally wet soil, pond and lake edges, ditches, borrow pits, swampy woods, bogs, other freshwater wetlands; 0-20 m; Ala., Ark., Del., Fla., Ga., La., Md., Miss., Mo., N.J., N.C., Okla., S.C., Tex., Va.; Mexico; West Indies (Hispaniola).
Pluchea foetida var. imbricata has not been treated as distinct from typical P. foetida by recent authors (e.g., A. Cronquist 1980; R. K. Godfrey and J. W. Wooten 1981; R. P. Wunderlin et al. 1996). Although plants similar to the type can be found scattered in Florida and Georgia, a populational integrity does not appear to occur, and intermediate forms exist. Nevertheless, field biologists should be aware of the putative distinctions of var. imbricata to make more critical observations regarding its status.
Fibrous-rooted perennial 3-10 dm, finely glandular and often somewhat cobwebby-puberulent; lvs oblong to elliptic, lance-ovate, or ovate, 4-10 נ1-4 cm, sharply callous-denticulate, reticulate-veiny, rounded to acute at the tip, closely sessile and ±cordate-clasping; heads several or many in a short and broad, leafy infl; invol 5-8 mm, finely glandular or viscid-puberulent; disk 6-12 mm wide; cors ochroleucous; 2n=20. Permanently wet soil, often in meadows or swampy woods; s. N.J. to Fla. and Tex., chiefly near the coast, but sometimes inland, as in Mo.; W.I. Aug., Sept., or in the south all year.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.