FLORA OF THE DISTRICT OF COLUMBIA. 283 



4. Erigeron ramosus (Walt.) B. S. P. Daisy fleabane. 



Fields; common. May-Oct. Widely distributed in the U. S. and Can. {E. 



s'rigosus Muhl.) 



16. LEPTILON Raf. 



1. Leptilon canadense (L.) Britton. Horseweed. 



Waste and cultivated ground; very abundant. Aug.-Sept. A common weed in 

 cultivated and waste ground nearly throughout N. Amer. (Erigeron canadensis L.) 



Flowers white, in very numerous small heads. The minute rays are likely to be 



overlooked. 



17. BACCHARIS L. 



1. Bacctaris halimifolia L. Groundsel bush. 



Collected at Little Falls, Accotink, near Cabin John, and at Bennings; rare. Along 

 the coast, Mass. to Tex.; W. Ind. 



18. GIFOLA Cass. 



1. Gifola germanica (L.) Dumort. Herba impia. 



Collected at Mount Vernon, Occoquan Creek, and on High Island. May-Sept. 

 Native of Eur. ; naturalized in the eastern U. S. (Filago germanica L.) 



19. PLUCHEA Cass. 



1. Pluchea camphorata (L.) DC. Marsh fleabane. 



In marshes; Mount Vernon and Marshall Hall. Aug.-Sept. Mass. to Mex. 

 A coarse annual, with small clustered heads of purplish flowers. 



20. ANTENNARIA Gaeitn. Everlasting. Pussy-toes. 



Inflorescence consisting of a single head. Stem very slender, with a few appressed 



linear leaves 1- A. solitaria. 



Inflorescence consisting of several or numerous heads, those of the pistillate plants in 

 corymbs or racemes. 

 Plants relatively small; mature basal leaves mostly 1.5-4 cm. long, 5-10 mm. 

 broad, with only the midvein conspicuous above. 

 Stolons mostly short, leafy throughout, forming broad mats; leaves obovate, 



abruptly wedge-shaped to the narrowly winged petiole 2. A. neodioica. 



Stolons long, slender, with well-developed leaves only at the tip; leaves oblan- 

 ceolate, often broadly so, passing gradually into the broadly winged petiole. 



3. A. neglecta. 

 Plants much larger and stouter; mature basal leaves of pistillate plants 5-12 cm. 

 long, 2-4 cm. broad, with 3 well-defined main nerves evident above. 

 Upper surface of basal leaves bright green, usually glabrous at all stages, some- 

 times slightly cobwebby when young 4. A. arnoglossa. 



Upper surface of basal leaves dull green, closely covered with a thin tomentum, 

 this partially persistent to the following year. 

 Plants very robu8t;»mature basal leaves 2-4 cm. broad; pistillate inflorescence 

 subcapitate or densely corymbose, the heads averaging about 1 cm. high. 



5. A. fallax. 



Plants comparatively slender; mature basal leaves narrower (1.5-3 cm. broad); 



pistillate inflorescence loosely corymbose (often diffusely so with age), the 



heads averaging about 8 mm. high 6. A. plantaginifolia. 



1. Antennaria solitaria Rydb. 



Damp sterile rocky banks, usually in the shade of beeches; several localities, mostly 

 from Rock Creek Park eastward. May. Pa. to Ohio, south to the Gulf states. 



2. Antennaria neodioica Greene. 



Open fields, brushy banks, and open woods, often under pines; fairly common 

 throughout. May. Northeastern N. Amer. 



The local form, described as ^1. alsinoides Greene, does not seem specifically distinct. 



