12a. Basal leaves, or most of them, merely serrate or crenate, and not obviously lobed --13. 12b. All the leaves lobed or divided --16. 13a. Stem-leaves resembling the basal ones, and not lobed (1-2 dm. high; summer) =Sea-side Crowfoot, Ranunculus cymbalaria.= 13b. Stem-leaves deeply divided into oblong or linear segments --14. 14a. Flowers 1.5 cm. wide or more (1-3 dm. high; spring) =Buttercup, Ranunculus rhomboideus.= 14b. Flowers 1 cm. wide or less (2-5 dm. high; spring) --15. 15a. Foliage glabrous or minutely pubescent; 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 buttercups are all classified here --22. 17a. Flowers 2 cm. broad or larger (Buttercup) --18. 17b. Flowers 1 cm. broad or smaller --19. 18a. Terminal 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.=