2 BULLETIN- 1012, IT. S. DEPARTMENT OF AGRICULTURE. 



at that time was determined by systematic botanists as Z. venenosus. 

 Later systematic work has shown that the species used was not the 

 true venenosus, but was Z. gramineus. Of the other species used, 

 Z. elegans and Z. coloradensis are so closely allied that they are 

 considered by many botanists as not specifically distinct. There is 

 no question, however, of the specific distinction between Z. grami- 

 neus, Z. elegans, and Z. paniculatus. From further work it seemed 

 probable that there was a much greater difference in toxicity of the 

 species than was apparent at the time Bulletin 125 was published, 

 and it became a matter of considerable importance to determine the 

 comparative toxicity of the different forms. 



All these species are so closely allied that they are not likely to be 

 separated by anyone who has not a fairly good knowledge of botany. 

 It follows, of course, that ordinarily all these forms are grouped under 

 the term ''death camas " without perception of the difference be- 

 tween the species. It is a matter of much scientific and practical 

 interest to know how they differ. 



Z. 'paniculatus is the most widely distributed and is the most 

 common form of death camas in the intermountain region and in 

 part of the western slope. Z. elegans is not so abundant but is the 

 common species on the higher mountain ranges of the West. Both 

 Z. elegans and Z. paniculatus grow in considerable quantity in the 

 neighborhood of the Salina Experiment Station, Utah, where a 

 somewhat extended study of the plants has been made. The proof 

 that these species are either more or less toxic than Z. gramineus, 

 which grows in Montana, would be of very great practical importance 

 to the stockmen who use the ranges where these plants are found. 



The experimental work was conducted on the same general lines as 

 the work in Montana, and the results have proved to be of consider- 

 able importance. Still further work is necessary on the species of 

 this genus, but the results obtained regarding these two species are 

 definite and conclusive. All the work here reported was done on 

 plant material collected in Utah. Inasmuch, however, as experience 

 with poisonous plants indicates that difference in locality has little 

 effect on the degree of toxicity, the conclusions reached here un- 

 doubtedly will apply equally well to these species wherever they may 

 be found. It may be added that Zygadenus intermedins, on which 

 work has been done by other authors, is considered by systematists 

 as being identical with Zygadenus gramineus. 



ZYGADENUS PANICULATUS. 



DESCRIPTION AND DISTRIBUTION OF THE PLANT.J 



Zygadenus paniculatus, shown in Plate I, is an erect perennial herb 

 with leafy stems arising from fibrous-coated bulbs. The linear leaves 



2 The description of Z. panic ulatus and its distribution was prepared by W. W. Eggleston, of the Bureau 

 of l'laut Industry. Mr. Eggleston has made a detailed study of the genus Zygadenus. 



