Coreopsis sect. Coreopsis
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 red-brown 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 red-brown 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.
Mostly c, e North America.
Species 7 (7 in the flora).
|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|