1. Aureolaria flava (L.) Farw. (smooth false foxglove)

A. flava var. macrantha Pennell

A. calycosa (Mack. & Bush) Pennell

Gerardia flava L.

G. flava var. calycosa (Mack. & Bush) Steyerm.

Pl. 471 b–d; Map 2152

Plants perennial. Stems 50–150 cm long, glabrous, usually somewhat glaucous. Leaf blades 6–15 cm long, deeply pinnately lobed, the lobes linear to narrowly elliptic or narrowly lanceolate, the margins otherwise entire or few-toothed, the upper surface moderately roughened with minute, stiff, broad-based, nonglandular hairs, the undersurface sparsely roughened to glabrous or nearly so. Bracts linear to narrowly lanceolate, entire or with a few teeth or slender lobes toward the base. Flower stalks 4–12 mm long at flowering, elongating to 5–16 mm at fruiting, relatively stout, at least toward the tip, straight or more commonly curved upward, glabrous. Calyces 9–16 mm long, glabrous, the lobes shorter than to slightly longer than the tube, entire. Corollas 35–60 mm long, the lobes glabrous, except along the margins. Fruits 12–20 mm long, glabrous. Seeds 1.7–2.7 mm long, with coarse, winglike ridges. 2n=24. June–September.

Scattered in the southeastern portion of the state north and west to Ste. Genevieve, Washington, Douglas, and Ozark Counties; also a single specimen from Newton County (eastern U.S. west to Wisconsin and Texas; Canada). Mesic to dry upland forests and edges of glades, fens, and sinkhole ponds.

Pennell (1928) separated A. flava into three varieties, of which he recorded only var. macrantha from Missouri, based on single specimens from Madison, Scott, and Wayne Counties. However, Pennell also segregated populations from mostly the Ozark portions of Arkansas and Missouri as a separate species, A. calycosa. The relatively widespread var. macrantha was said to have somewhat larger flowers than in var. flava. Aureolaria calycosa, to which Pennell (1928) assigned the majority of the Missouri populations, was said to differ in a suite of mostly quantitative characters, including relatively deeply lobed leaves, relatively small (40–50 mm) corollas glabrous within, relatively long awnlike anther bases, and relatively small seeds. Based on his experience with Missouri material in the field and herbarium (as Gerardia), Steyermark (1963) concluded that there was no basis for the segregation of var. macrantha from the typical variety and that the other taxon should be treated as var. calycosa rather than as a species. However, even he admitted that there was considerable morphological overlap between his concepts of var. calycosa and var. flava and that the characters said to distinguish the taxa varied independently of one another.