BUTTERCUP FAMILY 



(x) Plants aquatic, or the stems creeping 



and rooting in the mud 

 in. Leaves 3-lobed, the lobes often 



notched R. natans 



n. Leaves 3-5-divided, the segments 

 deeply cleft into oblong or linear 

 divisions R. multifidus 



(y) Plants not aquatic or creeping and 



rooting in the mud R. Pilrshii 



m. Achenes round, swollen, without a 



distinct margin 

 r. Petals large to medium, much 



longer than the sepals 

 (r) All leaves deeply cleft or di- 

 vided 



h. Leaves 2-3-ternately divided R. adoneus 

 i. Leaves 3-7-cleft or -divided R. eximius 

 (s) Some of the basal leaves only 



coarsely toothed 

 h. Achenes smooth 



(h) Plant smooth R. nivalis 



(i) Plant hairy R. ovdlis 



i. Achenes hairy R. affinis 



s. Petals small, scarcely longer than 



the sepals 

 (r) Some of the basal leaves 



merely coarsely toothed R. abort ivus 

 (s) All the basal leaves lobed or 



divided R. scelerdtus 



n. Achenes flattened and with a dis- 

 tinct margin 

 r. Beak of the achene hook-like 



(r) Petals 3-5 mm. long R. Dougldsii 



(s) Petals 6-12 mm. long R. acriformis 



s. Beak of the achene straight or 



nearly so 

 (r) Petals longer than the sepals ; 



head of achenes globose 

 h. Beak about as long as achene R. mdximus 



