122 



RANUNCULACEAE. 



aceoiis. 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. BATBACHIUM 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 wateb-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. 

 Achenes subulate-beaked : stems erect or ascending. 

 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. 

 Basal leaves with truncate or cuneately narrowed 

 blades : foliage pubescent : receptacle glabrous. 

 Basal leaves with all blades lobed or divided. 



Foliage glabrous : stem hollow : flowers relatively 



small. 

 Foliage more or less pubescent : stem not hollow : 

 flowers relatively lai'ge. 

 Beak of the achene hooked. 

 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. 

 Petals much longer than the sepals : head 

 of fruit subglobose. 

 Stems spreading and creeping, stolon- 



iferous. 

 Stems erect, not stoloniferous. 



Sepals spreading. 9. 



Sepals reflexed. 10. 



Achenes with beaks over % as long as the 

 achene-bodies, tlie beaks sometimes par- 

 tially deciduous. 

 Plants stoloniferous : foliage glabrous or 



nearly so. 11. 



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. 



Stems with spreading pubescence : 

 achene thick-margined : filaments not 

 dilated upward. 13. 



5. 



R. reptans. 



R. ohtusiusculus. 



R. abortivus. 

 R. micrdnthus. 



R. sceleratus. 



R. recurvatus. 



7. R. pcnnsylvanictis. 



8. R. repens. 



R. acris. 

 R. bulbosus. 



R. scptentrionalis. 



R. fascicularis. 

 R. hispidus. 



