108 The Ohio Journal of Science [Vol. XVII, No. 4, 



Ranunculus (Tourn.) L. Crowfoot, Buttercup. 



Perennial or annual herbs with simple, or usually compound 

 or divided alternate leaves. Flowers solitary, or few in a 

 cluster; yellow or rarely white; usually with five petals and 

 sepals; stamens and carpels numerous, distinct, spirally 

 arranged. Achenes tipped with a minute or elongated style. 



1. Leaves entire, terrestial or swamp plants, stems rooting at the 



nodes. R. obtusiuscidus. 

 1. Leaves finely dissected, aquatic plants, achenes callous margined. 



R. delphinifoJius. 



1. Some or all of the leaves divided or lobed, terrestial plants or in 



wet places. 2. 



2. Some or all basal leaves merely crenate or entire. 3. 



2. Leaves all lobed or divided. 5. 



3. Basal leaves cordate or orbicular, crenate, occasionally some may 



be 3-lobed, flowers inconspicuous, achenes smooth. 4. 



3. Basal leaves 3-lobed, divisions linear, the lowest may be entire, 



flowers conspicuous. R. arvensis. 



4. Basal leaves cordate, stems glabrous. R. abortiviis. 



4. Basal leaves more or less orbicular, not cordate; stems villous 



below. R. micranthus. 



5. Flowers inconspicuous, less than 3-S inch broad. 6. 



5. Flowers conspicuous, 3^-1 inch broad. 8. 



6. Stems glabrous, achenes merely apiculate. R. sceleratus. 



G. Stems densely hirsute, achenes with short or recurved beak. 7. 



7. Divisions of leaves wedge-shaped or lanceolate, deeply incised, fruit 



oblong or cylindrical. R. pennsylvanicus. 

 7. Divisions ovate, lobed, fruit globose. R. recurvatus. 

 S. Carpels with a short style or beak. 9. 

 S. Carpels with a long prominent st^ie or beak. 11. 

 9. Stems erect; divisions of the leaves deeply and abundantly cleft. 10. 

 9. Stems recumbent or creeping by stolons; divisions of the leaves 



only moderately cleft, the lobes rather broad. R. re pens. 

 U). Stem with a thick bulbous base; leaves appearing pinnate, ultimate 



divisions narrow; clayx reflexed. R. bulbosus. 



10. Stem without bulbous base; leaves palmately divided, the ultimate 



seginents linear; calyx spreading, not reflexed; inflorescence much 

 branched. R. acris. 



11. Stem leaves sessile, lowest basal leaves may be entire. R. arvensis. 



11. Leaves all petioled and divided. 12. 



12. Leaf segments broad, bases cuneate. 13. 



12. Leaf segments narrow, appearing pinnate; roots thickened or 



fascicled. R. fascicularis. 



13. Stems glabrous or jjubescent; achenes with a long stout style. 



R. septentrionalis. 

 13. Stems usually denseh^ villous or hispid; achenes abruptly tipped 

 by a subulate style. R. hispidus. 



