1 Style persistent; leaves various (see below).

  2 Style straight or slightly sinuous, neither jointed nor tightly twisted, the tip straight; basal leaves with a cordate or reniform terminal lobe 7-15 cm wide and 1-several lateral lobes generally < 1 cm long (rarely to 2 cm long); cauline leaves much reduced, flabellate, with clasping base and rounded apex; leaves thick, subcoriaceous, the upper surface dark green and glossy; petals 13-20 mm long, bright yellow; [of crevices and ledges on high elevation cliffs (less commonly grassy balds)]; [subgenus Micracomastylis]

  2 Style with a tight kink or twist, the straight portion above the kink more-or-less deciduous, leaving a hook; basal leaves variable, trifoliate, pinnatifid, simple or with a large terminal lobe (to 8 cm wide) and much smaller lateral lobes; cauline leaves trifoliate to simple, mostly sessile or petiolate base, with acute or acuminate apex; leaves herbaceous, the upper surface medium green, not notably glossy; petals 1-10 mm long, white, cream, pale yellow, bright yellow, lavender, maroon, or purple; [of mesic to boggy forests, or less commonly, grassy balds (G. geniculatum)].

    3 Calyx lobes 2-4 mm long, lacking bractlets between the lobes; head of achenes elevated above the calyx on a 1-2 mm stipe; flowering Apr-May; fruiting May-Jun; [subgenus Stylipus]

    3 Calyx lobes 3-15 mm long, with bractlets between the lobes; head of achenes more-or-less sessile; flowering May-Aug; fruiting late May-Sep; [subgenus Geum].

      4 Portion of the style above the kink 3-7 mm long; calyx campanulate, cup-like in flower and fruit (sometimes becoming slightly and irregularly reflexed late in fruit), the calyx lobes 5-10 mm long, green to purple; petals cream to yellow or often with a substantial suffusion of rose, lavender, or purple; lower portion of style with long, gland-tipped hairs.

        5 Portion of the style above the kink 4-7 mm long; calyx lobes 5-10 mm long, green or purple-darkened; [of nw. NC and adjacent TN]

        5 Portion of the style above the kink 3-4 mm long; calyx lobes 9-15 mm long, purple; [of ne. WV northward]

      4 Portion of the style above the kink 1-2 mm long; calyx reflexed soon after anthesis, the calyx lobes 3-9 mm long, green; petals white, cream, or yellow; lower portion of style glabrous or with long, eglandular hairs.

          6 Larger stipules > 10 mm wide, coarsely toothed or even lobed; mid-cauline leaves very coarsely toothed, with 1-5 teeth per cm of margin

          6 Larger stipules 2-10 (-12) mm wide, entire to toothed; mid-cauline leaves less coarsely toothed, with 3-7 teeth per cm of margin.

             7 Plant in flower.

               8 Petals bright yellow, 5-9 mm long

               8 Petals white or cream (often drying pale yellow), 2-7 (-7.5) mm long.

                 9 Petals (3-) 4-7 (-7.5) mm long; pedicels puberulent (sometimes also slightly hirsute); [of moist to dry forests]

                 9 Petals (2-) 2.5-4 (-5.5) mm long; pedicels densely hirsute with spreading or slightly reflexed hairs, and also puberulent; [of wetlands]

             7 Plant in fruit.

                   10 Pedicel predominantly puberulent, also sometimes with scattered longer hairs; cauline leaves mostly 3-foliolate or simple; receptacle densely hispid with yellowish, stiff hairs (best seen by removing a several achenes to expose the receptacle surface); [widespread and common in our area, primarily occurring in moist to wet forests]

                   10 Pedicel moderately to densely hirsute with spreading to reflexed hairs 1-2.5 mm long, and also puberulent; cauline leaves mostly pinnately compound, the leaflets mostly elongate and often also laciniately divided; receptacle glabrous or sparsely to densely hispid; [rare in our area, primarily northern and/or montane, primarily in bogs and boggy meadows].

                     11 Hairs on the achene extending upward onto the lower portion of the style; pedicel sparsely hirsute with spreading hairs; receptacle densely hispid

                     11 Hairs on the achene absent or at least not extending upward onto the lower portion of the style; pedicel densely hirsute with spreading to reflexed hairs; receptacle glabrous to sparsely hispid

1 Leaves 2- to 3-ternately compound; [tribe Spiraeeae]

1 Leaves 1-compound, either simply pinnately compound or simply palmately compound,

  2 Principal (basalmost) leaves pinnately compound, with (3-) 5-many leaflets (upper stem leaves sometimes 3-foliolate).

    3 Principal leaves with leaflets of markedly disparate shape and size (large leaflets alternating with much smaller leaflets, or a large terminal leaflet and much smaller lateral leaflets).

      4 Lateral leaflets alternating between small and large, the terminal leaflet similar in size and shape to the larger lateral leaflets; terminal leaflet < 3 cm wide; hypanthium either conical or turbinate, armed with hooked bristles, the pistils 2, or hemispheric, the pistils >5.

        5 Leaves glabrous or sparsely pubescent beneath; flowers many in racemes; hypanthium conical or turbinate, armed with hooked bristles, the pistils 2; [tribe Sanguisorbeae]

        5 Leaves silvery sericeous beneath; flowers solitary and axillary; hypanthium hemispheric, the pistils >5; [tribe Potentilleae]

      4 Leaflets variable in size and shape, usually the terminal leaflet much larger than any of the lateral leaflets; terminal leaflet 3-20 cm wide; hypanthium either sauce-r-shaped or hemispheric to conical; pistils 5 or more.

          6 Pistils 5-15, in a circle on a saucer-shaped hypanthium, ripening into upright fruits that resemble follicles but are indehiscent; corolla white or pink; plant 10-20 dm tall; [tribe Ulmarieae]

          6 Pistils many, densely covering the hemispheric to conical hypanthium, ripening into achenes terminated by the persistent style; corolla white, cream, pale yellow, bright yellow, lavender, maroon, or purple; plant 2-10 dm tall; [tribe Colurieae]

    3 Principal leaves with leaflets of generally similar shape and size (the lowest leaflets may be smaller but of similar shape and toothing to the other leaflets).

             7 Stems and leaf rachises and petioles armed with retrorse prickles.

             7 Stems and leaves unarmed.

               8 Foliage and stems viscid-pubescent with brownish hairs; inflorescence a cyme; petals 5, cream-colored; [tribe Potentilleae]

               8 Foliage not viscid-pubescent (if hairy, the hairs not brown or viscid); inflorescence of very many (>100) small flowers in a spike, the rachis hidden by the tightly packed flowers; petals 0; [tribe Sanguisorbeae].

                 9 Leaflets pinnatifid (each leaflet incised nearly to the midvein); stamens 2 or 4 per flower

                 9 Leaflets toothed (the incisions not nearly to the midvein); stamens either 4 or 15-20 per flower (in well-developed, staminate flowers).

                   10 Leaflets 0.8-2 cm long; spike 1-2 cm long, 1-2× as long as broad, globose; stamens 15-20 per flower (in well-developed staminate flowers), the filaments 3-4 mm long; sepals green to pinkish-purple; [cultivated, occasionally escaped]

                   10 Leaflets 3-10 cm long; spike 6-30 cm long, elongate; stamens 4 per flower, the filaments 8-10 mm long; sepals white (sometimes fading greenish); [native]

  2 Principal (basal-most) leaves palmately compound, with 3-7 (-9) leaflets.

                     11 Principal leaves subsessile, 3-foliolate; fruit of follicles; leaves cauline; [tribe Gillenieae]

                     11 Principal leaves distinctly petiolate, the petiole often longer than the leaflets, 3-7 (-9)-foliolate; fruit of achenes; leaves basal and cauline.

                       12 Principal leaves 5-7 (-9)-foliolate; [tribe Potentilleae]

                          13 Petals maroon-colored, shorter than sepals; plants sprawling with horizontal stems bearing rooting nodes; [wetlands from n. PA, n. NJ, sc. IN and sc. OH northward]

                          13 Petals yellow or white, not shorter than sepals; plants trailing or upright, if bearing horiztonal stems with rooting nodes then petals not maroon-colored and plants not in wetlands; [dry habitats, collectively widespread]

                       12 Principal leaves 3-foliolate.

                            14 Plants in flower.

                              15 Petals yellow.

                                16 Pistils (10-) numerous; [tribe Potentilleae]

                              15 Petals white (or slightly pinkish).

                                  17 Calyx lobes not subtended by bractlets; [tribe Rubeae]

                                  17 Calyx lobes subtended by 5 sepaloid bractlets; [tribe Potentilleae].

                                    18 Leaves evenly serrate with many serrations; [widespread]

                                    18 Leaves with 3 (-5) teeth at the apex, otherwise entire

                            14 Plants in fruit (or sterile).

                                       19 Leaflets entire, except for 3 (-5) teeth at the apex; [tribe Potentilleae]

                                       19 Leaflets evenly serrate or crenate, each well-developed leaflet with > 7 teeth.

                                         20 Calyx lobes not subtended by bractlets.

                                           21 Fruit an aggregate of fleshy, adherent drupelets; leaflets acuminate at apex; [tribe Rubeae]

                                         20 Calyx lobes subtended by 5 sepaloid bractlets; [tribe Potentilleae].

                                             22 Fruit an aggregate of dry achenes

                                             22 Fruit an accessory fruit of achenes borne on the surface of a fleshy, red receptacle.

                                               23 Fresh fruit reddish inside; leaflets serrate, 2.5-12 cm long; sepaloid bracts narrowing to apex, untoothed

                                               23 Fresh fruit whitish inside; leaflets crenate, 2-4 cm long; sepaloid bracts widest at apex, 3-5-toothed