158 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



8. TRAUTVETTERIA Fisch. & Mey. 



1. Trautvetteria carolinensis (Walt.) Vail. False bugbane. 



Low wet ground; Mount Vernon; Difficult Run. June-July. Southern states, 

 north to Pa. 



9. RANUNCULUS L. Buttercup. 



Basal leaves, at least most of them, entire or shallo^Iy toothed. 

 Upper stem leaves entire or very shallowly toothed. Plants glabrous. 



Plants annual; flowers 4-6 mm. broad; fruiis not beaked 1. R. pusillus. 



Plants perennial, the stems rooting at the joints; flowers 12-15 mm. broad; fruits 



beaked 2. R. obtusiusculus. 



Upper stem leaves compound or deeply lobed. 

 Stems glabrous; basal leaves cordate at the base; receptacle hairy. 



3. R. abortivus- 

 Stems loosely hairy, at least below; leaves not cordate at the base; receptacle 



glabrous 4. R. micranthus. 



Basal leaves compound or deeply lobed. 

 Leaves glabrous; fi-uits not margined. Petals about as long as the sepals. 



5. R. sceleratus. 

 Leaves hairy, at least along the veins beneath; fruits with an evident margin. 

 Beak of the fruit long, slender, and recurved; basal leaves lobed, not divided. 



Petals shorter than the sepals 6. R. recurvatus. 



Beak of the fruit long and straight, or very short and recurved; basal leaves 

 usually divided to the base or composed of distinct leaflets. 

 Beak of the fruit long and straight. Petals much longer than the sepals. 

 Roots slender; plants, at least in age, producing long runners; petals 1)roadly 



obovate 7. R. septentrionalis • 



Roots fleshy-thickened; plants erect or nearly so, without runners; petals 



ol)long 8. R. hispidus. 



Beak of the fruit short and recurved. 

 Plants wiih long runners. Petals much longer than the sepals. .9. R. repens. 

 Plants erect or ascending, wilhout runners. 



Petals about 3 mm. long; head of fruits cylindric, much longer than thick. 



10. R. pennsylvanicus. 

 Petals 7-12 mm. long; head of fruits globose, about as thick as long. 



Stem bulblike at the base; middle division of the basal leaves stalked; 



sepals reflexed, almost as long as the petals 11. R. bulbosus. 



Stem not bulblike at the base; divisions of the l^asal leaves all sessile; 

 sepals not reflexed, much shorter than the petals 12. R. acris. 



1. Ranunculus pusillus Poir. 



Marshes along the Potomac and Eastern Branch. Apr.-May. Eastern U. S. 



2. Ranunculus obtusiusculus Raf. 



Marshes along the Eastern Branch and Hunting Creek. June-July. Eastern U. S. 

 {R. ambigens S. Wats.) 



3. Ranunculus abortivus L. 



Woods or moist soil; common. Apr.-May. Eastern N. Amer. {R. ruderalis 

 Greene.) 



R. ruderalis was based upon specimens from Linden and Takoma Park. It is a form 

 with dull green leaves, those of the more common form being lustrous. 



4. Ranunculus micranthus Nutt. 



Rich woods along the upper Potomac; frequent. Apr.-May. Eastern N. Amer., 

 west to Colo. (R. abortivus viicranthus A. Gray; R. holmii Greene.) 

 R. holmii was based upon material from our region. 



