37 



17a. Flowers 2 cm. broad or larger (Buttercup) 18. 

 17b. Flowers 1 cm. broad or smaller 19. 



ISa. Terminal lobe of leaf stalked (25 dm. high, early 



summer) Buttercup^ Ranunculus bulbosus. 



18b. Terminal lobe of leaf sessile (510 dm. high; all sum- 

 mer) 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 wood's (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 sum- 

 mer) 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 sum- 

 mer) 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 (36 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 on long stalks 27. 



