FLOEA OF THE DISTRICT OF COLUMBIA. 159 



6. Ranunculus sceleratus L. 



Marshes along the Potomac and Eastern Branch; frequent. May-July. Widely 

 distributed in temperate N. Anier.; also Eur. and Asia. 



6. Ranunculus recurvatus Poir. 



Damp woods and thickets; common. Apr.-M^y. Eastern N. Amer. 



7. Ranunculus septentrionalis Poir. 



Low ground along the Potomac; common. Apr.-May. Eastern N. Amer. (R. 

 repens nitidus and R. repens, in part, of Ward's Elora.) 



8. Ranunculus hispidug Michx. 



Usually in dry woods and thickets; common. Apr.-May. Eastern U. S. (R. 

 repens hispidus and R. repens, in pai-t, of Ward's Flora.) 



9. Ranunculus repens L. 



Marshes or waste ground; occasional. Apr. -June. Widely distributed in N. 

 Amer., largely naturalized from Eur. 



10. Ranunculus pennsylvanlcus L. f. 



Swamp near Aqueduct Bridge, August, 1S88 (Holm). Widely distributed in tem- 

 perate N. Amer. 



11. Ranunculus bulbosus L. 



Fields and waste ground; abundant. Apr.-June. Native of Eur. ; widely natural- 

 ized in eastern N. Amer. 



12. Ranunculus acris L. 



Fields and waste ground; common. May-July. Native of Eur.; widely natural- 

 ized in N. Amer. ' 



10. FICARIA Huds. 

 1. Ficaria verna Huds. Lesser celandine. 



Shaded banks. Rock Creek Park. Apr. Native of Eur. and Asia; occasionally 

 adventive in the northeastern U. S. {Ranunculus ficaria L.; F. fi,caria Karst.) 



11. THALICTRTJM. Meadow-rue. 



Leaflets waxy-glandular beneath. Fruits not stalked; filaments slender, drooping. 



1. T. revolutum. 

 Leaflets glabrous beneath or very finely hairy, never glandular. 



Filaments club-shaped, not drooping, the apex nearly as wide as the anthers. 

 Fruits not stalked; leaflets mostly longer than broad, usually finely hairy 



beneath 2. T. polygamum. 



Filaments threadlike, soon drooping. 



Stem leaves on long slender stalks; plants flowering in April or early May. Leaflets 

 glabrous, mostly as broad as long; fruits not stalked, not glaucous. 



3. T. dioicum. 

 Stem leaves mostly sessile, sometimes on short stout stalks; plants flowering 

 mostly from late Majr to July. 



Fruits sessile; leaflets mostly longer than broad 4. T. dasycarpum. 



Fruits short-stalked; leaflets mostly as broad as long or broader. 



6. T. caulophylloides. 



1. Thalictrum revolutum DC. 



Woods and low ground; common. June. Eastern U. S. {T. purpurascens ceriferum 

 Ai'stin.) 



2. Thalictrum polygamum Muhl. 



Pwamps or low woods; frequent. May-July. Eastern N. Amer. (T. cornuti of 

 Ward's Flora.) 



3. Thalictrum dioicum L. 



Moist woods or thickets along Rock Creek and the upper Potomac. Apr.-May. 

 Eastern U. S. 



