XXVI. NATIVE AND CULTIVATED RANUNCULI OF 

 NORTH AMERICA AND SEGREGATED GENERA. 



K. C. DAVIS. 



Few groups of plants are perhaps less understood than this 

 one. The range of variation in characters is rather limited and 

 yet the number of species is very great. Six genera have taken 

 from Ranunculus about thirty-six species and yet that genus re- 

 tains more species than any other of the order Ranunculaceae. 

 About 350 names have already been given to American plants 

 of this group. 



KEY TO GENERA. 



A. Akencs transversely wrinkled ; roots fibrous ; aquatic or ditch 



herbs; flowers white Batrachium. 



AA. Akenes not transversely wrinkled. 



B. Developed carpels not longitudinally ribbed or striated. 



C. Roots not a cluster of thickened tubers, or several times longer 



than thick. 

 D. Flowers mostly yellow or white; akenes compressed, never 



lanceolate, srgooth, papillose or spiny Ranunculus. 



DD. Flowers white; akenes lanceolate, utricular; style hooked. 



Kumlienia. 

 CC. Roots a cluster of thickened tubers; leaves crenate, cordate; 



cotyledon only i Ficaria. 



BB. Developed carpels longitudinally ribbed or striated. 



C. Leaves pinnately compound or lobed ; akenes terete, style 



persistent, slender, recurved Cyrtorhyncha. 



CC. Leaves not as above ; akenes compressed. 



D. Akenes with beaks somewhat reflexed ; leaves rounded and 



lobed Arcteranthis. 



DD. Akenes minutely sharp-pointed; leaves crenate-dentate, 



oval-cordate to renif orm Oxygraphis. 



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