Annuals or perennials. Leaves basal and cauline or mostly cauline, opposite; blades simple or ± pinnately or pedately lobed (with 3–9+ lobes). Calyculi of (6–) 8 (–9) bractlets. Phyllaries 8. Ray-florets 8 (more in “double” cultivars), neuter; laminae yellow, sometimes each with redbrown or purple near base, ± cuneate, broadest distal to middles, apices usually ± 3-lobed (middle lobes entire or toothed). Disc-florets (30–) 60–150+; corollas yellow, apices yellow or redbrown to purple, lobes 5; style-branch apices ± penicillate to short-conic or truncate-mucronate. Paleae basally ± lanceolate to linear, distally attenuate (± filiform). Cypselae obovate to oblong (often cupped), margins ± winged (or wingless and margins adaxially ± corky), wings ± chartaceous, usually entire, rarely irregularly toothed to pectinate, ± spreading, not ciliolate, faces glabrous, smooth or ± papillate; pappi 0, or usually falling, of (1–) 2 cusps or subulate to lanceolate scales (0.1–0.5+ mm). x = 13.
Distribution
Mostly c, e North America
Discussion
Species 7 (7 in the flora).
Selected References
None.
Lower Taxa
Key
| 1 | Annuals (rarely persisting); ray laminae yellow, usually each with proximal red-brown to purple flecks, spot, or band | > 2 |
| 1 | Perennials (sometimes flowering first year); ray laminae yellow (without red-brown or purple near bases) | > 3 |
| 2 | Leaves mostly in proximal 3/4–7/8 of plant heights; calyculi of lance-deltate to linear bractlets 6–9(–12+) mm; disc corolla apices red-brown to purple; cypselae wingless | Coreopsis basalis |
| 2 | Leaves mostly in proximal 1/5–1/3(–1/2) of plant heights; calyculi of deltate to lance-oblong bractlets 4–6(–8) mm; disc corolla apices yellow; cypselae winged | Coreopsis nuecensis |
| 3 | Plants usually stoloniferous; wings of cypselae 0 or involute, ± corky | Coreopsis auriculata |
| 3 | Plants not stoloniferous (± rhizomatous or bases ± cormose); wings of cypselae ± spreading, ± chartaceous. | > 4 |
| 4 | Aerial nodes proximal to first peduncle usually 1–3(–5+); leaves mostly on proximal 1/4–1/3(–1/2) of plant heights; cypselae (2.6–)3–4 mm | Coreopsis lanceolata |
| 4 | Aerial nodes proximal to first peduncle usually (5–)6–12+; leaves mostly on proximal 1/2–7/8 of plant heights; cypselae 2–3 mm | > 5 |
| 5 | Blades of leaves rarely simple, usually irregularly 1(–2)-pinnately or ± -pedately lobed with (3–)5–9+ lobes, rarely simple, simple blades or terminal lobes narrowly lanceolate to linear or filiform, (0.5–)2–8 (–12+) mm wide | Coreopsis grandiflora |
| 5 | Blades of leaves usually simple, rarely with 1–2(–3+) lateral lobes, simple blades or terminal lobes oblong-elliptic or ovate to elliptic or lanceolate, (2–)5–35 mm wide | > 6 |
| 6 | Simple leaf blades or terminal lobes oblong-elliptic or ovate to elliptic, 45–95+ × 22–35 mm; phyllaries 9–12 mm | Coreopsis intermedia |
| 6 | Simple leaf blades or terminal lobes lance-elliptic to oblanceolate or lanceolate, 15–60(–80) × 2–25(–35)mm; phyllaries 5–8+ mm | Coreopsis pubescens |
"broader" is not a number.