122 RANUNCULACEAE. 



aceous. Sepals 5-10, petal-like. Petals wanting. Filaments clavate. Achene- 

 cluster peduncled. 



1. S. thalictroides (L.) Hoffmg. Plants 1-2.5 dm. tall: leaflets 1-2.5 cm. 

 long, mostly 3-lobed: sepals 5-10, white or pinkish, 9-15 mm. long: achenes 

 4^6 mm. long, or sometimes longer, ribbed. Common, in moist places and 

 thickets. Spr. and sum. RUE-ANEMONE. WILD-ROSE. 



10. BATRACHIUM S. F. Gray. Perennial aquatic or ditch herbs. Leaf- 

 blades dissected or palmately lobed, the segments often narrow. Flowers on 

 peduncles opposite the leaves. Sepals 5. Petals usually 5, mainly white, each 

 claw with a pit. Stamens several-many. Achenes oblique, compressed, trans- 

 verse-wrinkled, often nearly or quite beakless. 



1. B. trichophyllum (Chaix) Bosch. Leaves flaccid, 3-5 cm. long, the seg- 

 ments mostly 10-15 mm. long; stipules short and broad^ pubescent: petals 5-8 

 mm. long : head of achenes 4-5 mm. in diameter. N. Rare, in springs and 

 spring-runs. Limestones. (Eurasia) . Sum. WHITE WATER-CROWFOOT. 



11. RANUNCULUS [Tourn.] L. Annual or perennial herbs. Leaf- 

 blades entire, lobed, or divided. Flowers solitary or variously disposed. 

 Sepals mostly 5, deciduous. Petals as many as the sepals or more, or rarely 

 fewer, each with a pit near the base. Carpels several or numerous. Achenes 

 generally flattened, smooth, papillose, or echinate. BUTTERCUP. CROWFOOT. 



Mud plants : leaves with entire or shallowly toothed blades. 



Achenes minutely beaked : stems trailing. 1. R. reptans. 



Achenes subulate-beaked : stems erect or ascending. 2. R. obtusiusculus. 



Terrestrial plants : leaves with all or some of the blades 



lobed or divided. 

 Basal leaves with all or some of the blades crenate. 



Basal leaves with cordate blades : foliage glabrous or 



nearly so : receptacle pubescent. 3. R. dbortivus. 



Basal leaves with truncate or cuneately narrowed 



blades : foliage pubescent : receptacle glabrous. 4. R. micranthus. 



Basal leaves with all blades lobed or divided. 



Foliage glabrous : stem hollow : flowers relatively 



small. 5. R. sceleratus. 



Foliage more or less pubescent : stem not hollow : 



flowers relatively large. 



Beak of the achene hooked. 6. R. recurvatus. 



Beak of the achene straight or slightly curved. 

 Achenes with beaks less than % as long as the 



achene-bodies. 

 Petals about as long as the sepals : head 



of fruit oblong or cylindric. 7. R. pennsylvanicus. 



Petals much longer than the sepals : head 



of fruit subglobose. 

 Stems spreading and creeping, stolon- 



iferous. 8. R. repens. 



Stems erect, not stoloniferous. 



Sepals spreading. 9. R. acris. 



Sepals reflexed. 10. R. bulbosus. 



Achenes with beaks over % as long as the 

 achene-bodies, the beaks sometimes par- 

 tially deciduous. 

 Plants stoloniferous : foliage glabrous or 



nearly so. 11. R. septentrionalis. 



Plants not stoloniferous : foliage copiously 

 pubescent, except sometimes in age. 

 Stems with silky or appressed pubes- 

 cence : achene not thick-margined : 

 filaments dilated upward. 12. R. fascicularis. 



Stems with spreading pubescence : 

 achene thick-margined : filaments not 

 dilated upward. 13. R. hispidus. 



