IMPORTANT POISONOUS PLANTS 



141 



Fig. 19o. Absinthium (.Artemisia absinthium). Plant, leaves, and flowering branch. 

 (Faguet). 



Arctium Lappa L. Burdock. 



Produces itching. Contains the alkaloid lappine. Common weed in the 

 U. S. 



Cirsium lanceolatum (L.) Hill. Bull Thistle. 



Commonly naturalized in the north from the Atlantic to the Pacific. It acts 

 injuriously in a mechanical way. Other species like C. Nelsoni, Canada Thistle 

 (C. arvense), C. scariosum, etc., all act in a similar way. Some species contain 

 HCN. 



Centaurea solstitialis L. Knapp Weed. 



Common in alfalfa meadows westward. Acts injuriously in a mechanical 

 way. Some species, according to Greshoff, contains HCN. 



