1. Coreopsis grandiflora Hogg ex Sweet (bigflower coreopsis)

C. grandiflora var. harveyana (A. Gray) Sherff

Pl. 275 d; Map 1160

Plants perennial, with a short, sometimes branched rootstock. Stems 30–100 cm long, glabrous (hairy elsewhere). Leaves distributed at (5)6–10 nodes along (1/2–)2/3 of the length of the stems, sessile or short-petiolate, the lowermost leaves sometimes with relatively long petioles. Leaf blades (2–)3–9 cm long, narrowly oblanceolate or narrowly elliptic (in undivided leaves) to oblong-ovate or broadly ovate (in divided leaves) in outline, those of the basal and lowermost stem leaves sometimes unlobed, but those of most leaves 1 or 2 times deeply pinnately or palmately divided into (3–)5–9 relatively slender, narrowly linear to narrowly lanceolate lobes or divisions, in entire leaves the blade angled or tapered at the base; in divided leaves, the lateral lobes or divisions shorter than to longer than the terminal lobe or division, 0.5–3.0(–5.0) mm wide, narrowly linear to narrowly oblong-lanceolate, angled or tapered at the base, rounded or more commonly angled or tapered to a usually sharply pointed tip, glabrous or the margins sometimes with a few spreading hairs at the leaf base. Inflorescences of solitary heads or appearing as loose, open clusters, the heads with the stalk mostly 8–20 cm long. Involucre with the outer series of bracts 4–10 mm long; the inner series of bracts 7–12 mm long. Chaffy bracts narrowly triangular, long-tapered from an abruptly broadened, flat basal portion to a sharply pointed tip. Ray florets with the corolla 12–25 mm long, with 3–5 deep, sometimes irregular (appearing jagged) teeth or lobes around the tip, uniformly yellow to orangish yellow. Disc florets with the corollas 3.5–5.0 mm long, 5-lobed, yellow, sometimes with yellowish orange lobes. Style branches tapered abruptly to a sharply pointed, sterile tip. Pappus of 1 or 2 scalelike teeth 0.1–0.3 mm long. Fruits 2.0–3.5 mm long, the base and tip appearing curled or arched inward at maturity, the angles with broad, pale wings having entire or occasionally slightly irregular margins, the inner face with a bulbous thickening at 1 or both ends, dark brown to black, 1 or both surfaces smooth to minutely pebbled, sometimes with few to numerous small, lighter-colored tubercles, especially on the inner surface. 2n=26. April–July.

Scattered mostly in the Unglaciated Plains Division and the eastern portion of the Ozarks (southeastern U.S. west to Kansas and Texas; introduced farther north and west). Upland Prairies, glades, ledges and tops of bluffs, and openings of dry upland forests; also railroads and roadsides.

Morphological variation within and between populations of C. grandiflora is complex. Sherff (1955) and Smith (1976) attempted to segregate a series of varieties and forms based on supposed differences in leaf segment width, pubescence, and the size of the pappus teeth. Steyermark (1963) separated Missouri materials into two of these infraspecific taxa, with var. grandiflora differing from var. harveyana based on its somewhat broader leaf lobes and a distribution in the Unglaciated Plains Division (vs. the eastern Ozarks). More recent collections have shown that plants with both narrower and broader leaf segments occur throughout the range in Missouri. Although there may be some basis in recognizing some of the other infraspecifc taxa from other states that differ in pubescence and pappus characters, the separation of Missouri materials into varieties seems arbitrary and without merit.