290 CONTRIBUTIONS FROM THE NATIONAL, HERBARIUM. 



1. Helenium autumnale L. Sneeze weed. 

 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 Beltaville. 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-Bcented; 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. arveusis. 



1. Anthemis cotula L. Matweed. Dog fennel. 

 Waste groimd; common. Jime-July. Native of Eur.; widely naturalized in N. 



Amer. CMaruta 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 {J. B. S. Norton). 



39. CHRYSANTHEMUM L. 



The common cultivated chrysanthemums belong to this genus. 



1. Chrysanthemum leucanthemum pinnatlfidum 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. TANACETUM 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. ABTEMISIA 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-scented 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 Hoaslyn, August, 1899 (Steele). Native of Eur. and Asia; adven- 

 tive in the eastern U, S. 



