minal lobe of leaf stalked (2-5 dm. high, early summer)
=Buttercup, Ranunculus bulbosus.=

18b. Terminal lobe of leaf sessile (5-10 dm. high; all summer)
=Buttercup, Ranunculus acris.=

19a. Plant glabrous, succulent; stem hollow (1-5 dm. high; spring and
summer) =Cursed Crowfoot, Ranunculus sceleratus.=

19b. Plant pubescent (Buttercup) --20.

20a. Fruits tipped with a prominent recurved beak; plant of shady
woods (2-6 dm. high; flowers in late spring)
=Buttercup, 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
=Buttercup, Ranunculus pennsylvanicus.=

21b. Fruits in a globose or short-ovoid head, on an obovoid receptacle
=Buttercup, 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 (Buttercup) --24.

23a. Stem-leaves numerous (1-2 dm. tall; late spring and summer)
=Crowfoot, Ranunculus purshii.=

23b. Stem-leaves one or none, the principal leaves all basal (about 1
dm. high; flowers in summer) =Buttercup, Ranunculus lapponicus.=

24a. Style short, obviously curved --25.

24b. Style long and slender, straight or nearly so (common
spring-flowering buttercups, 2-5 dm. high) --26.

25a. Stems creeping; flowers 2 cm. wide or more (spring)
=Buttercup, Ranunculus repens.=

25b. Stems ascending; flowers 1.5 cm. wide or less (3-6 dm. high;
summer) =Buttercup, Ranunculus macounii.=

26a. The two lateral divisions of the leaf sessile or nearly so
=Buttercup, Ranunculus fascicularis.=

26b. The two lateral divisions of the leaf o