290 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



1. Helenlum autumnale L. Sneezeweed. 

 Wet meadows; common. Aug.-Oct. Nearly throughout the U. S. and southern 



Can. 



2. Helenium nudiflorum Nutt. Purple sneezeweed. 

 Collected above Plummers Island, east of Chevy Chase, and near Beltsville. July- 

 Sept. N. C. to Tex., adventive northward. 



37. ACHILLEA L. 



1. Achillea millefolium L. Yarrow. 



Woods, open fields, and roadsides; abundant. June-Aug. Eastern N. Amer.; 

 also in Eur. and Asia. 



Characterized by the finely dissected, plumelike, strong-scented leaves. The rays 

 are often tinged with pink. 



38. ANTHEMIS L. 



Plants ill-scented; leaves thrice pinnately lobed; receptacle without chaff near the 

 margin; achenes roughened 1. A. cotula. 



Plants not ill-scented; leaves once or twice pinnately lobed; chaff subtending all 

 the disk flowers; achenes smooth 2. A. arvensis. 



1. Anthemis cotula L. Mayweed. Dog fennel. 

 Waste ground; common. June-July. Native of Eur.; widely naturalized in N. 



Amer. (Maruta cotula DC.) 



2. Anthemis arvensis L. Corn camomile. 

 Waste and cultivated ground; common. May-July. Native of Eur., widely 



naturalized in the U. S. 



Anthemis tinctoria L., a European species with yellow rays, was collected at College 

 Park in 1915 (/. B. S. Norton). 



39. CHRYSANTHEMUM L. 



The common cultivated chrysanthemums belong to this genus. 



1. Chrysanthemum leucanthemum pinnatifidum Lecoq. & Lam. Ox-eye daisy. 



Fields; very abundant. May-Oct. Native of Eur. and Asia; widely naturalized 

 in the U. S. (Leucanthemum vulgare of Ward's Flora.) 



Chrysanthemum parthenium (L.) Bernh., feverfew, has been found a few times in 

 waste ground about Washington. Native of Eur. ; adventive or escaped from culti- 

 vation locally in the U. S. and southern Can. 



Chrysanthemum balsamita L. , costmary, was collected in waste ground at Fifteenth 

 Street and Florida Avenue, September, 1899 (Steele). Native of the Old World; 

 sparingly escaped from cultivation in the eastern U. S. 



40. TANACETTJM L. 

 1. Tanacetum vulgare L. Tansy. 



Occasional on roadsides and in waste ground. July-Aug. Native of Eur.; often 

 naturalized or escaped from cultivation in the U. S. 



41. ARTEMISIA L. 



1. Artemisia annua L. Annual wormwood. 



Waste ground about Washington and Alexandria and at Glen Echo. Aug.-Sept 

 Native of Asia; adventive or escaped from cultivation in many parts of the U. S. 



An annual plant with sweet-Bcented foliage. 



Artemisia caudata Michx. was reported from the vicinity of Alexandria, by Holm. 

 No specimens have been seen by the writer. Artemisia vulgaris L. was collected 

 along a roadside near Rosslyn, August, 1899 (Steele). Native of Eur. and Asia; adven- 

 tive in the eastern U. S. 



