40 PASTORAL AND AGRICULTURAL BOTAN^ 



journals. At least nine species of Zygadenus are poisonous and the above 

 mentioned one may be taken as the type of their action. The plant is 

 also called wild onion, wild leek. It arises from a tunicated bulb and has 

 narrow, erect, basal leaves and a scape, a foot or more high, becoming a 

 spike of yellowish- white flowers, which blossom about June ist (Fig. 15). 

 It matures its fruit in July and then the whole aerial part of the plant dies 

 down to the ground. It is native to the west from Assiniboia and Neb- 



FIG. 16. Sheep No. 168 at 1.30 P.M., showing weakness in forelegs after being fed 

 Death Camas (Zygadenus venenosus). (After Marsh, C. Dwight, Clawson, A. B. and 

 Marsh, Hadleigh: Zygadeus or Death Camas, Bulletin 125, U. S. Department of Agricul- 

 ture, 1915, Plate V, Fig. I.) 



raska westward to the Pacific coast. The chief period of danger is in 

 May and June when its dark green leaves are attractive to stock. Cattle 

 are susceptible to the poison and some deaths have been reported, but 

 cases among cattle are uncommon. Swine are said to eat the bulbs 

 without bad results, but horses are poisoned. Sheep are the animals most 

 frequently poisoned (Figs. 16 and 17). Detailed experiments by agents 

 of the United States Department of Agriculture show that the principal 

 symptoms are salivation, nausea, muscular weakness, coma and sometimes 



