UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 1012 



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Contribution from the Bureau of Animal Industry 

 JOHN R. MOHLER, Chief 



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Washington, D. C. 



PROFESSIONAL PAPER 



April 17, 1922 



THE DEATH CAMAS SPECIES, ZYGADENUS PANICULATUS 



AND Z. ELEGANS, AS POISONOUS PLANTS. 



By C. Dwight Marsh, Physiologist in Charge of Investigations of Stock Poisoning by 

 Plants, and A. B. Clawson, Physiologist, Pathological Division. 



CONTENTS. 



Page. 



Purpose and scope of paper 1 



Zygadenus paniculatus .- 2 



Description and distribution of plant 2 



Experimental feeding 3 



Discussion and results 10 



Symptoms 10 



Duration of symptoms 12 



Time required to produce symptoms ... 13 



Toxic and lethal dosage 13 



Zygadenus elegans 16 



Description and distribution of plant 16 



Experimental feeding 17 



Discussion and results 20 



Symptoms 20 



Duration of symptoms 21 



Time required to produce symptoms. . . 21 



Results of autopsy 22 



Toxic and lethal dosage 22 



Comparative toxicity of Z. gramineus, Z. 



paniculatus, and Z. elegans 24 



Z. elegans not especially dangerous for 



sheep 25 



Summary 25 



PURPOSE AND SCOPE OF PAPER. 



In Bulletin 125, United States Department of Agriculture, page 

 35, the following statement was made with regard to the comparative 

 toxicity of different species of Zygadenus: 1 



In the course of the experiments four species of Zygadenus were used — Z. venenosus, 

 Z . elegans, Z . paniculatus, and Z. coloradensis — by far the greater part of the work be- 

 ing done with Z. venenosus. The number of experiments with Z. elegans and Z. pani- 

 culatus was very small, and the material, especially in the case of Z. paniculatus, had 

 been shipped a long distance, so that there was some question of the water content 

 of the plant. Apparently, however, Z . elegans and Z . paniculatus do not differ materially 

 in toxicity from Z. venenosus. Z. coloradensis, however, produced no toxic effects 

 whatever, with the exception of slight symptoms in one sheep, although the plant 

 was fed in quantities several times as great as the toxic dose of Z. venenosus. 



It is evident that in the feeding of cattle with Z. coloradensis at Mount Carbon in 

 1909, the results of which are given in Table I, the quantities fed were too small to 

 produce results, even if the plants were as poisonous as Z. venenosus. In the experi- 

 ment of 1910, however, a large quantity was fed, and sufficiently large quantities in 

 single days to produce symptoms of poisoning if the plant were as toxic as Z. venenosus. 



Most of the work reported in Bulletin 125 was on the species of 

 Zygadenus growing in the Yellowstone Valley, Montana, which 



1 Zygadenus, or Death Camas, by C. Dwight Marsh, A. B. Clawson, and Hadleigh Marsh, Bulletin 125, 

 United States Department of Agriculture, 1915. 

 67283°— 22— Bull. 1012 1 



