1. Fleischmannia incarnata (Walter) R.M. King & H. Rob. (pink thoroughwort)

Eupatorium incarnatum Walter

Pl. 267 d, e; Map 1120

Plants perennial, fibrous-rooted, often reclining on other vegetation. Stems usually few, several-branched, 30–120 cm long, loosely ascending, often from a spreading base, sparsely to moderately pubescent with short, curly hairs. Leaves opposite (the nodes well separated), sessile to short- or long-petiolate. Leaf blades 0.8–7.0 cm long, triangular-ovate to more or less heart-shaped, the uppermost sometimes only triangular-lanceolate, truncate to more commonly shallowly cordate at the base (the uppermost leaves sometimes broadly angled), tapered to a usually sharply pointed tip, the margins shallowly scalloped or bluntly toothed, the upper surface glabrous or minutely hairy, sometimes only along the veins, the undersurface moderately to densely hairy, especially along the veins, usually not glandular, with mostly 3 main veins. Inflorescences small panicles or stalked clusters at the branch tips, usually more or less flat-topped. Heads with 13–25 disc florets. Involucre 3–5 mm long, the bracts 18–30 (the head often also subtended by 1 or a few other narrower bracts), in usually 2 or 3 unequal to subequal, overlapping series, narrowly oblong-elliptic to narrowly lanceolate, tapered to a bluntly or more commonly sharply pointed tip, all but the outermost noticeably but finely few-nerved or few-ribbed, glabrous or sparsely short-hairy. Receptacle flat or slightly convex. Corollas purple or lavender-blue (rarely white elsewhere). Pappus of numerous capillary bristles. Fruits 1.8–2.5 mm long, finely 5(–7)-ribbed, slightly wedge-shaped in profile (usually slightly and unevenly tapered at the base), glabrous, the ribs smooth or with a few minute, ascending teeth, lighter colored, the body otherwise dark brown to black. 2n=20. August–October.

Uncommon in the Mississippi Lowlands Division and also in McDonald and Ozark Counties (southeastern U.S. west to Illinois, Missouri, and Texas; Mexico). Swamps, bottomland forests, bases of bluffs, and banks of streams and rivers; also ditches, railroads, and roadsides.

Molecular studies have suggested that Fleischmannia forms a natural group with Ageratum and Conoclinium that is only distantly related to Eupatorium in the strict sense within the tribe Eupatorieae (Schilling et al., 1999; Schmidt and Schilling, 2000; Ito et al., 2000b). This is reflected in the overall similarity in general appearance between F. incarnata, A. conyzoides, and C. coelestinum, which all have bluish purple flowers and ovate-triangular main leaves. Steyermark (1963) noted that plants of F. incarnata (as Eupatorium incarnatum) tend to have an odor resembling vanilla when dried and that the leaves generally are thinner, darker green, and more heart-shaped than those of C. coelestinum. He also noted that plants of A. conyzoides tend to be more densely hairy on the stems and leaves.