KANUNCULACEAE 441 



3. Batrachium flaccidum ( Pers. ) Kupr. Kesembling the next preceding species. 

 Leaves with larger and more slender petioles ; blades with very long flaccid segments, col- 

 lapsing when withdrawn from the water. 



In streams, Massachusetts to Washington, North Carolina and Lower California. Also in Europe, 

 Asia and Africa. Spring to fall. 



22. HALERPESTES Greene. 



Perennial sometimes scapose herbs, with runners. Leaves mainly basal : blades cre- 

 nate, dentate or lobed, long-petioled. Flowers small, yellowish, solitary or 2-7 together 

 on scapes or scape-like peduncles. Sepals usually 5, spreading, tardily deciduous. Petals 

 5-12, each bearing a small nectar-pit near the base. Stamens and pistils numerous. Head 

 of fruit oblong, oval or subglobose. Achenes compressed, sometimes swollen, longitudi- 

 nally striate, without a hard coat. 



1. Halerpestes Cymbalaiia (Pursh) Greene. Foliage glabrous. Plants somewhat 

 fleshy, spreading by runners. Leaves mostly basal ; blades slender-petioled, ovate, cor- 

 date-oval or reniform, crenate, 4-18 mm. long : flowers 1-7, about 6-8 mm. broad, borne 

 on scapes 2.5-15 cm. long, these sometimes bearing one or more leaves toward the base : 

 head of fruit oblong, 6-16 mm. long : achenes compressed, somewhat swollen, distinctly 

 striate, minutely sharp-tipped. 



On sandy shores, Labrador to New Jersey, west along the St. Lawrence River and the Great Lakes 

 to Minnesota and the Northwest Territory, and in saline soil throughout the western half of the conti- 

 nent, extending into Mexico. Also in Asia and South America. Summer. 



23. RANUNCULUS L. 



Annual or perennial herbs, with erect or creeping stems. Leaves alternate : blades 

 simple, entire, lobed or divided, or dissected. Flowers solitary or variously disposed. 

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

 white or red, conspicuous or minute, each provided with a nectariferous pit and a scale 

 at the base of the blade. Carpels several or numerous, 1-ovuled. Achenes capitate or 

 spicate, generally flattened, smooth, papillose or echinate, each tipped with a minute or an 

 elongated style. CROW-FOOT. BUTTERCUP. 



Aquatic plants : submerged leaves with dissected blades ; floating leaves with lobed blades. 



1. R. delphinifoliut. 

 Terrestrial or mud plants : leaves with entire, toothed, lobed or divided blades. 



Mud plants : leaves with entire or denticulate blades. 

 Annuals : achenes beakless. 



Petals mostly 1-3, pale yellow, barely 2 mm. long : stamens 5-10. 



Head of fruit oblong or cylindric : achenes suborbicular, less than 1 mm. long. 



2. R. tener. 

 Head of fruit subglobose': achenes obovoid, fully 1 mm. long. 3. R. pusillus. 



Petals 5, bright yellow, over 2 mm. long : stamens numerous. 4. R. oblonffifolius. 



Perennial : stems creeping : achenes with subulate beaks. 5. R. obtusiusculua. 



Terrestrial plants : leaves with all or some of the blades lobed or divided. 

 Basal leaves with all or some of the blades crenate. 



Petals conspicuous, much longer than the sepals. 6. JR. Harveyi. 



Petals inconspicuous, shorter than the sepals or about equalling them 



in length. 

 Styles very short. 



Basal leaves with cordate blades : foliage glabrous or nearly so. 7. R. abortivus. 

 Basal leaves with truncate or cuneately narrowed blades : foliage 



pubescent. 8. R. micranthus. 



Styles subulate, hooked, nearly ^ as long as the achene-body. 9. R. AllegJieniensis. 



Basal leaves with all blades lobed or divided. 

 A. Achenes smooth and glabrous. 



Foliage glabrous : stem hollow : flowers relatively small. 10. R. scelcratus. 



Foliage more or less pubescent : stems not hollow : flowers relatively 



large. 



Beaks of the achenes hooked. 11. R. recurvatus. 



Beaks of the achenes straight or slightly curved. 



Achenes with beaks less than % as long as the bodies. 



Petals about as long as the sepals : head of fruit oblong or 



cylindric. 12. R. Pennsylvanicus. 



Petals much longer than the sepals : head of fruit subglobose. 13. R. buibosus. 

 Achenes with beaks over % as long as the bodies ; beaks some- 

 times partially deciduous. 



Carpels or achenes few. 14. R. palmatus. 



Carpels or achenes numerous. 



a. Corolla '2.5 cm. broad or smaller : petals 5 : head of fruit 



subglobose. 

 * Plants stolon if erous : foliage glabrous or nearly sc. 15. R. septentrionalis. 



