1 Flowers bilaterally symmetrical, the upper sepal hooded or spurred; [tribe Delphinieae].

  2 Upper sepal hooded or helmet-shaped; petals hidden by the sepals; perianth blue or creamy white; stems weak, clambering, reclining, vining, or ascending in a curve

  2 Upper sepal spurred; petals at least partly exserted from the sepals; perianth blue, pink, white, or greenish; stems strong, erect, normally straight

1 Flowers radially symmetrical, no perianth parts spurred or hooded (except the 5 sepals spurred in Myosurus).

    3 Petals present, white or yellow, larger and more conspicuous than the sepals; sepals present, green; [in other words, with a second, green, less conspicuous perianth whorl below the largest and colored perianth whorl; note that some Anemone have a calyx-like involucre of 3 bracts subtending each flower]; [tribe Ranunculeae].

      4 Basal leaves linear to linear-spatulate, mostly 4-8 cm long, 1-3 mm wide; receptacle elongate, 1-6 cm long (superficially resembling a Plantago inflorescence)

      4 Basal leaves various, but not as above; receptacle globose to sub-cylindric, mostly < 1 cm long

        5 Sepals 3 (-4); petals 7-12; achenes pubescent, beakless; leaves simple, cordate, unlobed; [introduced garden plants]

        5 Sepals (3-) 5 (-6); petals typically 5-9 (10 in some "doubled" forms); achenes smooth or variously ornamented with spines, papillae, or tubercles, sometimes also pubescent; leaves various, usually not at once simple, cordate, and unlobed (except in Halerpestes); [native or introduced].

          6 Cauline leaves absent; basal leaves cordate, unlobed

          6 Cauline leaves present, well-developed; basal leaves not simultaneously cordate and unlobed

    3 Petals absent (or modified into relatively inconspicuous nectaries or staminodia); sepals present and petaloid (white, yellow, yellow-green, cream, or blue).

             7 Petaloid sepals 3-5 mm long, caducous; stamens white and showy; [tribe Ranunculeae]

             7 Petaloid sepals 6-40 mm long, not caducous; stamens not notably white and showy.

               8 Leaves opposite, distributed along the stem; style plumose; [tribe Anemoneae]

               8 Leaves all basal, or with a few alternate or whorled involucrate leaves on the stem; style not plumose.

                 9 Petaloid sepals white, bluish, or blue; basal leaves 3-5 (-7)-lobed; [tribe Anemoneae]

                   10 Leaves lobed, and also toothed and variously cleft; leaves not variegated

                   10 Leaves lobed, the margins of the lobes entire; leaves often prominently variegated

                 9 Petaloid sepals yellow, green, or whitish (sometimes marked with purple); basal leaves unlobed, or palmately cleft into 5-11 (-many) segments.

                     11 Leaves cordate-reniform, unlobed; sepals bright yellow; petals absent; [native, of bogs and marshes]; [tribe Caltheae]

                     11 Leaves palmately or pedately lobed or divided; sepals green, greenish, dull yellow, or whitish; petals modified into tubular nectaries; [introduced, rarely persistent or escaped from cultivation].

                       12 Sepals 5, green or maroon, persistent in fruit; cauline leaves present; leaf margins sharply and finely serrate; [tribe Helleboreae]

                       12 Sepals 5-8, yellow; cauline leaves either present, alternate, or absent, except for the involucre of 3 bracts which immediately subtends the flower.

                          13 Cauline leaves absent, except the 3 involucral bracts immediately subtending the flower; [tribe Cimicifugeae]