6 BULLETIN 125, U. S. DEPARTMENT OF AGRICULTURE. 



more extended, as shown in Plate II, which is reproduced from a 

 photograph of a Montana plant. Plate III shows the plant after 

 the seed is formed. 



COMMON NAMES OF ZYGADENUS. 



The species of Zygadenus are known under a large number of pop- 

 ular names. The most common perhaps is death camas. In the 

 Northwest perhaps lobelia is the name used even more generally than 

 death camas. Other names are soap plant, alkali grass, water lily, 

 squirrel food, wild onion, poison sego, poison sego lily, mystery grass, 

 and hog's-potato. Z. glaberrimus is said to be called cow-grass. 



POISONOUS SPECIES OF ZYGADENUS. 



The following species of Zygadenus are said to be poisonous: Z. 

 elegans, Z. falcatus, Z. fremontii, Z. glaberrimus, Z. intermedius, Z. 

 mexicanus, Z. nuttallii, Z. paniculatus , Z. venenosus. 



This list is given hi accordance with the statements of various 

 authors, and no attempt has been made to revise it from the stand- 

 point of the systematic botanist. Apparently all species of this genus 

 may be presumed to be poisonous. Even Zygadenus coloradensis , 

 which has been shown not to be injurious to stock in Colorado, has 

 the same poisonous principle as the other species, but in smaller 

 quantity. 



LOSSES OF LIVE STOCK BY ZYGADENUS. 



As already stated, there is reason to think that deaths of cattle and 

 horses from Zygadenus poisoning are not numerous. With sheep, 

 however, the losses .are very heavy, but it is impossible to make even 

 an approximate estimate of these losses. It is probable that they 

 are much greater than is generally supposed, for in the sheep-grazing 

 regions many, perhaps most, of the herders do not know the plant and 

 consequently do not recognize it as the cause of illness and death in 

 the bands under their charge. The lupines, without any doubt, have 

 been blamed for many of the cases of poisoning by Zygadenus. 



Chesnut and Wilcox (1901, p. 53) state that 636 sheep died from 

 Zygadenus poisoning in Montana in 1900 and that 3,030 were poisoned. 

 In one locality in Wyoming 500 sheep died out of a total of 1,700 

 poisoned, and in one county it was said that 20,000 died in 1909. The 

 writers of this paper investigated a case in Montana in which 500 sheep 

 died within a few hours, the probable cause being Zygadenus. 



There is no doubt that this plant is one of the sources of heaviest 

 loss to sheep owners, especially in Wyoming and Montana. There is 

 good reason, too, for thinking that many of the losses in Oregon, 

 Utah, and California which have been ascribed to other plants were 

 really caused by Zygadenus. 



