15a. Foliage glabrous or minutely p.u.b.escent; basal leaves cordate =Small-flowered Crowfoot, Ranunculus abortivus.=
15b. Foliage villous; basal leaves barely cordate or not at all =Small-flowered Crowfoot, Ranunculus micranthus.=
16a. Stem erect or essentially so --17.
16b. Stem prostrate, creeping, or ascending. Early in spring stems may be found which appear almost erect. Common spring-flowering b.u.t.tercups are all cla.s.sified here --22.
17a. Flowers 2 cm. broad or larger (b.u.t.tercup) --18.
17b. Flowers 1 cm. broad or smaller --19.
18a. Terminal lobe of leaf stalked (2-5 dm. high, early summer) =b.u.t.tercup, Ranunculus bulbosus.=
18b. Terminal lobe of leaf sessile (5-10 dm. high; all summer) =b.u.t.tercup, Ranunculus acris.=
19a. Plant glabrous, succulent; stem hollow (1-5 dm. high; spring and summer) =Cursed Crowfoot, Ranunculus sceleratus.=
19b. Plant p.u.b.escent (b.u.t.tercup) --20.
20a. Fruits tipped with a prominent recurved beak; plant of shady woods (2-6 dm. high; flowers in late spring) =b.u.t.tercup, Ranunculus recurvatus.=
20b. Fruits tipped with a straight or slightly curved beak; plants of marshes or wet soil (3-6 dm. high; flowers in summer) --21.
21a. Fruits in a short-cylindric head on a conical receptacle =b.u.t.tercup, Ranunculus pennsylvanicus.=
21b. Fruits in a globose or short-ovoid head, on an obovoid receptacle =b.u.t.tercup, Ranunculus macounii.=
22a. Leaves dissected into numerous linear or narrowly wedge-shape divisions; plants growing in water or very wet places (late spring and summer) =Water Crowfoot, Ranunculus delphinifolius.=
22b. Leaves palmately lobed, the terminal division not definitely stalked --23.
22c. Leaves compound, some or all of the divisions on definite stalks (b.u.t.tercup) --24.
23a. Stem-leaves numerous (1-2 dm. tall; late spring and summer) =Crowfoot, Ranunculus purshii.=
23b. Stem-leaves one or none, the princ.i.p.al leaves all basal (about 1 dm. high; flowers in summer) =b.u.t.tercup, Ranunculus lapponicus.=
24a. Style short, obviously curved --25.
24b. Style long and slender, straight or nearly so (common spring-flowering b.u.t.tercups, 2-5 dm. high) --26.
25a. Stems creeping; flowers 2 cm. wide or more (spring) =b.u.t.tercup, Ranunculus repens.=
25b. Stems ascending; flowers 1.5 cm. wide or less (3-6 dm. high; summer) =b.u.t.tercup, Ranunculus macounii.=
26a. The two lateral divisions of the leaf sessile or nearly so =b.u.t.tercup, Ranunculus fascicularis.=
26b. The two lateral divisions of the leaf on long stalks --27.
27a. Roots fibrous; plants of wet soil =b.u.t.tercup, Ranunculus septentrionalis.=
27b. Roots thickened; plants of dry woods or thickets =b.u.t.tercup, Ranunculus hispidus.=
28a. Leaves dissected into numerous narrowly linear acute divisions (4-7 dm. high; flowers large, bluish, in summer) =Love-in-a-mist, Nigella damascena.=
28b. Leaves lobed or divided, but the divisions not separated by definite stalks --29.
28c. Leaves truly compound, all their divisions separated by distinct stalks --39.
29a. Leaves all basal, their lobes (usually 3) entire (1-2 dm. high; flowers pink-purple, in earliest spring) (Hepatica) --30.
29b. Lobes of the leaf serrate or incised --31.
30a. Lobes of the leaf obtuse or rounded =Hepatica, Hepatica triloba.=
30b. Lobes of the leaf acute =Hepatica, Hepatica acutiloba.=
31a. Petals none; sepals 3, usually falling away as soon as the flower opens (2-4 dm. high; flowers greenish-white, in spring) =Golden Seal, Hydrastis canadensis.=
31b. Petals none; sepals petal-like, 4 or more (Anemone) --32.
31c. Petals present, but much smaller than the 5 petal-like sepals --38.
32a. Stem-leaves sessile or nearly so --33.
32b. Stem-leaves on definite petioles --35.
33a. Ovary tipped with a long slender hairy style; flowers bluish-purple (1-4 dm. high; early spring) =Pasque Flower, Anemone patens var. wolfgangiana.=
33b. Ovary with a short style, densely woolly; flowers red, greenish, or white (1-4 dm. high; late spring and summer) --34.
33c. Ovary tipped with a short style, glabrous or nearly so; flowers white (4-7 dm. high; late spring and early summer) =Anemone, Anemone canadensis.=
34a. Stem 1-flowered, sepals white =Anemone, Anemone parviflora.=
34b. Stem 3-flowered; sepals usually red =Anemone, Anemone multifida.=
35a. Achenes densely woolly; flowers appearing in summer --36.
35b. Achenes merely p.u.b.escent; stems 1-flowered; woodland species blooming in early spring (1-2 dm. high; flowers white) =Wood Anemone, Anemone quinquefolia.=
36a. Segments of the leaf broadly wedge-shape or ovate; flowers white (4-8 dm. high) --37.
36b. Segments of the leaf linear-oblong; flower red, greenish, or white; plants growing on the sh.o.r.es of the Great Lakes =Anemone, Anemone multifida.=
37a. Segments of the basal leaves wedge-lanceolate; head of fruit cylindric =Anemone, Anemone cylindrica.=
37b. Segments of the basal leaves ovate-lanceolate; head of fruit ovoid or oblong =Anemone, Anemone virginiana.=