140 MANUAL OF POISONOUS PLANTS 



Common in the south and said to be fatal to horses and mules. It imparts 

 its bitter flavor to milk. 



Helenium Hoopesii A. Gray. Mountain Sneezeweed. 



Common in the Rocky, the Uintah and Wasatch Mountains. Said to be 

 injurious to sheep. 



Achillea millefolium L. Yarrow. 



It is used as a forage plant, but causes an irritating sensation of the mem- 

 branes and much pain in the gastric and abdominal regions. It contains the 

 glucoside achillein, an amorphous bitter substance, and the alkaloid moschatin. 



Anthemis Cotula L. Mayweed. 



Has a very disagreeable odor and causes blistering of the skin. The plant 

 is carefully avoided by stock. 



Anthemis arvensis L. Corn chamomile. 



Occasionally escaped from cultivation. Seeds of this and other species 

 contain HCN. 



Dysodia chrysanthemoides Lag. Fetid Marigold. 



Common in the west, Dak, la.. Neb. to Mo., Tex. The leaf bracts and 

 other parts of the plant are provided with large pellucid glands which produce 

 the characteristic odor of the plant. 



Tanacetum vulgare L,. Common Tansy. 



Introduced into many parts of the north. Many serious and a few fatal 

 cases of poisoning are recorded by the use of tansy oil. The symptoms of 

 poisoning are varied, convulsions, violent spasms, dilation of the pupils, fre- 

 quent and feeble pulse. Eleven drachms of the oil in a girl produced death in 

 three and one-half hours. The effect on animals is salivation, vomiting, dilation 

 of the pupils, muscular twitchings, followed by chronic spasms, death appears 

 to be caused by paralysis of the heart and lungs. 



Artemisia biennis Willd. Biennial Wormwood. 



Probably poisonous. 



Artemisia tridentata Nutt. 



Sage brush used as forage by sheep. 



Artemisia Absinthium L. Common Wormwood. 



Occasionally cultivated. The volatile oil of the plant is a violent, narcotic 

 poison, and contains the glucoside absinthiin, the alkaloid abrotin, the bitter 

 principle santonin. 



Other species probably also poisonous. 



Arnica cordifolia Hook. Arnica. 



This species with yellow flowers is common in the Rocky Mountains. The 

 bruised leaves give off the odor of arnica. The European A. montana is sus- 

 pected. 

 1 Senecio Jacobaea L,. Staggerwort. 



Occasionally found in the east and causes the Pictou disease. The Squaw 

 Weed {S. aureus) is common in the north. The 6". plattensis, common in west- 

 ern Iowa to Montana and east to Ontario, has been associated by Dr. Day with 

 the Missouri Bottom disease. The species are numerous in the Rocky Mountains 

 and may be responsible for some diseases. It is to be noted that the 5*. guadalen- 

 sis of Mexico is fatal to stock. The exotic 5". toluccanus contains an alkaloid 

 with tetanus like action. 



