340 FLORA OF PHILADELPHIA. 



10a. Bidens teichosperma tenuiloba (A. Gray) Britton. M. p. 1003. 

 Swamps. Autumn. 

 New Castle— Qgletown, west and north piers. Frequent. 



11. Bidens aristosa (Michx.) Britton. M. p. 1003. Swamps. Autumn. 



Delaware— Lenni (W. Tr.). 



12. Bidens involucrata (Nutt.) Britton. M. p. 1003. Swamps. Late 



summer. 

 Delaware— Tinicum (P.). 



38. GALINSOGA B. & P. 

 1. Galinsoga parviflora Cav. M. p. 1004. Waste places. Summer and 



fall. 



39. HELENIUM L. Sneezeweed. 



Bays fertile; disk yellow. 1. H. autwmnale. 



Bays neutral; disk purple. 2. H. nudiflorvm. 



i. Helenium atjtumnale L. M. p. 1010. Alluvial banks. Autumn. 

 2. Helenium nudiflorum Nutt. M. p. 1010. Moist soil. Summer and fall. 

 Philadelphia— Haddington. Montgomery — Near Ardmore (Pr.). Dela- 

 ware— Valley of Cobb's Creek, Dr. Geo. Smith (P.). Chester— Atglen 



(St.). Mwi y\vtr^A^^' netr "' ^■^'^ ciri ^ ■■*■;'/?*/■ 

 i 



i 40. ACHILLEA L. 



L Achillea Millefolium L. Yarrow or Milfoil. M. p. 1013. Fields, 

 roadsides and waste places. Summer and fall. 



41. ANTHEMIS L. 



Bays neutral; plant glabrous or nearly so, fetid. 1. A. Cotula. 



Bays pistillate; plants pubescent. 2. A. arvensis. 



1. Anthemis Cotula L. May-weed. M. p. 1014. Fields, roadsides and 



waste places. Summer and fall. 



2. Anthemis arvensis L. Corn Chamomile. M. p. 1014. Fields and waste 



places. Summer. 

 Anthemis mixta L. Ballast. 



Philadelphia— Mifflin Street Wharf (Ja.). 



42. CHBYSANTHEMTJM L. 



Heads large, few or solitary at the ends of the stem or branches. 



1. C. Leucanthemwn. 

 Heads numerous, small, corymbose; plant escaped from gardens. 



2. C. Parthenwm. 



1. Chrysanthemum Leucanthemum L. Ox-eye or White Daisy. White- 



weed. M. p. 1015. Fields and meadows. Spring to fall. 



2. Chrysanthemum Parthenium (L.) Pers. Feverfew. M. p. 1015. 



Escaped from gardens. Summer. 

 Chrysanthemum segetum L. Ballast. 

 Camden— Camden, /. Burlc (He.). 



