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Key to Coreopsis

Asteraceae

Coreopsis

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1 Leaves all simple, 4-12 cm wide, and also coarsely serrate (some of the lower leaves sometimes pinnately lacerate basally); rays 5, not lobed at the tip
1 Leaves simple, lobed, divided, or compound, but the margins of the leaves, leaflets or lobes entire, never serrate; rays (5-) 8 (-13).
  2 Rays entire (or with 1-2 obscure teeth at the tip); disc corollas 5-lobed; plants perennials; rays yellow; leaves strictly opposite
  2 Rays with 3-5 lobes or teeth at the tip; disc corollas 4- or 5-lobed; plants annuals or perennials; rays yellow (sometimes with a red or brown blaze at base), pink, purple, or white; leaves opposite, alternate, or both together.
      4 Leaves pinnately or bipinnately lobed into linear segments or narrowly lanceolate segments (sometimes plants with a mix of 1-pinnate and simple leaves as in C. leavenworthii); cypselae either wingless or with conspicuous, entire wings; [section Calliopsis].
        5 Cauline leaves usually 1-pinnate or simple; rays yellow throughout (rarely with red-brown blotches); pappi of 2 subulate scales; [s. AL and s. GA s. through peninsular FL]
        5 Cauline leaves usually 1-2+ pinnate; rays with basal red-brown blotches; pappus lacking or of 1-2 scales; [either widespread or endemic to s. TX].
          6 Plants typically 30-100 cm tall, sparsely branched from the bases; cypselae with or without wings; pappi 0.1-0.2 mm long; [widespread]
          6 Plants typically 10-30 cm tall, usually branched from the bases; cypselae 2-3 mm long, bearing conspicuous wings; pappi 0.2-1 mm long; [s. TX and n. MX]
      4 Leaves simple or with 1-2 auriculate lobes at the base, but lacking linear or pinnate segments; [section Eublepharis].
             7 All of the major cauline leaves opposite (except in C. linifolia the lowermost few leaves may be alternate).
                 9 Leaf blades ovate (to elliptical), very gradually reduced upward, margins ciliolate, surfaces lacking tiny dark dots; achenes about 5 mm long; [se. SC south to Panhandle FL]
                 9 Leaf blades linear-oblanceolate to linear, rapidly reduced upward, margins glabrous, surfaces with numerous tiny dark dots (easiest to see on undersurface); achenes < 2.5 mm long; [se. VA south to ne. and Panhandle FL, west to e. TX]
             7 All of the major cauline leaves alternate.
                     11 Outer phyllaries deltoid and very short, less than 0.3× as long as the inner phyllaries; flowering late Sep-Jan; [endemic to FL]
                     11 Outer phyllaries lanceolate, 0.4-0.8× as long as the inner phyllaries; flowering early May-early Nov; [collectively widespread].
                       12 Basal/lower leaves (at least 4 nodes) absent at anthesis; mid-cauline leaves linear to linear-lanceolate, or broadly to narrowly elliptical; achene awns 0.2-1.0 mm long; flowering Sep-Oct; [swamp forests and streamside openings, fresh-tidal creek margins; or wet calcareous savannas]; [from se. NC south to n. FL].
                          13 Leaves 8-15+ cm long, 2-7 mm wide, the blades linear to linear-oblanceolate, 20-50× as long as wide; achene awns 0.2-0.4 mm long
                          13 Leaves 4-15 cm long, 10-45 mm wide, the blades broadly to narrowly elliptical, 5-15× as long as wide; achene awns 0.7-1.0 mm long
                       12 Basal/lower leaves present at anthesis; leaves rapidly reduced upward such that mid-cauline leaves are narrow or slender; achene awns 0.5-1.5 mm long; flowering early May-early Nov; [wet savannas, seepage slopes, pitcher-plant bogs, streamhead ecotones, pocosin ecotones]; [collectively more widespread].
                            14 Leaves (at least one major leaf per plant) with 1-few slender lobes near the base (rarely no lobed leaves present or at least readily visible); achene wing broad, > 3/4 the width of the achene body; achene awns averaging 0.5 mm; leaf texture firm but not thick and leathery; flowering early May-early Jul; [se. VA south to e. GA]
                            14 Leaves without basal lobes; achene wing narrow, < ½ the width of the achene body; achene awns averaging 1.5 mm long; leaf texture thick and leathery; flowering mid Aug-early Nov; [se. NC south to c. FL and west to s. MS; also rarely inland in GA, NC, SC, off the Coastal Plain]
                              15 All of the leaves simple or the plant with a mixture of simple leaves and leaves with 1-2 (-4) basal auricles or leaflets, these distinctly smaller than the terminal lobe or leaflet.
                                16 Stems with (5-) 6-12 nodes between the first node > 1 cm above the basal leaves and the first head.
                                  17 Phyllaries primarily 5-8 mm long; laminae of rays ca. 12-15 mm long; peduncles (7-) 12-15 cm long.
                                       19 Leaf blades (or terminal leaflets of compound leaves) more or less broadly elliptical, ca. 1.5-4 cm wide, acute; stem (and often also the leaves) rather densely hairy (to glabrate)
                                16 Stems with 1-5 (-8) nodes between the first node > 1 cm above the basal leaves and the first head.
                                         20 Annual; rays yellow, with a red-brown or purple blaze or spotting near the base.
                                           21 Leaves extending >1/2 way up the stem; bracts subtending the phyllaries 6-9 (-12) mm long; disc corollas with apices red-brown to purplish; cypselae wingless
                                           21 Leaves extending <1/2 way up the stem; bracts subtending the phyllaries 4-6 (-8) mm long; disc corollas with apices yellow; cypselae winged.
                                         20 Perennial (cormose or rhizomatous at base, and sometimes also stoloniferous); rays completely yellow, lacking a red-brown or purple blaze or spotting near the base.
                                               23 Plants lacking stolons; leaf blades (or terminal leaflets) > 3× as long as wide (basal leaves sometimes broader).
                                                 24 Leaves oblanceolate, infolded, only very rarely with basal lobes, 15-30× as long as wide; leaf surfaces completely glabrous; [endemic to calcareous glades of Jackson County, FL]
                                                 24 Leaves oblanceolate, not notably infolded, the larger often with basal lobes; leaf surfaces shortly pubescent at least along the veins; [widespread in our area]
                              15 Most or all of the leaves deeply lobed or dissected into distinct leaflets or divisions, the leaflets or divisions 3-20 or more, if only 3, then the lateral leaflets nearly or fully as large and well-developed as the terminal.
                                                    25 Disk flowers reddish; ray flowers usually with a basal red mark; leaflets of mid-cauline leaves 1-15 mm wide and about 1-10× as long as wide
                                                      26 Terminal leaflets of mid-cauline leaves 5-15 mm wide, < 3× as long as wide; lower stems more uniformly to densely pubescent; [mainly sandy soils or in disturbed situations east of the Mississippi River]
                                                      26 Leaflets of mid-cauline leaves 1-3 mm wide, 3-8× as long as wide; lower stems typically glabrous to slightly pubescent; [mainly calcareous soils, in TX]
                                                          28 Midstem and upper stem leaves with > 5 segments; plants erect; flowering May-late Jun; [of granite outcrops, sandy woods, and similar open disturbed areas; collectively more widespread].