18 BULLETIN 575, U. S. DEPARTMENT OF AGRICULTURE. 



performed with wild-cherry leaves, many of which have been with- 

 out results. Investigations by the department, however, have 

 proved beyond question that the leaves of wild cherry are extremely 

 poisonous, and there seems to be no doubt that, under certain cir- 

 cumstances, animals may be killed by eating this plant. These 

 cases ordinarily occur along drives that are bordered by wild cherry 

 and where there is very little else for the animals to eat. 



Sheepmen should by all means avoid, if possible, trails that are 

 lined with wild cherry, and if it is necessary to drive over these trails, 

 they should take great care that the animals are well supplied with 

 food before commencing the drive. Poisoning from wild cherry is 

 due to prussic acid, and death results very quickly. No treatment 

 is likely to modify the results. Plate XXIV shows one of the wild 

 cherries of the West. 



MILKWEED (ASCLEPIAS). 



There are persistent accounts in certain regions of losses, particu- 

 larly of sheep, by eating milkweed. There seems to be no question 

 of the accuracy of these accounts, although it has been impossible 

 thus far to verify the poisonous properties of milkweed by corral 

 experiments. 



The plant is Very distasteful to animals under ordinary conditions, 

 and where animals are confined in corrals it is almost impossible to 

 make them eat it. It seems to be true, however, that range animals, 

 when compelled by severe hunger, will sometimes eat enough to 

 occasion disastrous results. Plate XXV shows a picture of the com- 

 mon milkweed. 



WOODY ASTER (XYLORRfflZA PARREYI). 



The woody aster, shown in Plate XXVI, occurs in great abundance 

 in certain regions in Wyoming, and has been accused of causing losses 

 of sheep in those localities. There appears to be no doubt that the 

 plant is poisonous. It is a fibrous plant, however, and is very dis- 

 tasteful to sheep under ordinary circumstances, so there is very 

 little danger from it, provided the sheep are kept in a region where 

 sufficient feed is obtainable. 



COLORADO RUBBER PLANT, OR PLNGUE (HYMENOXYS FLORIBUNDA). 



This plant, shown in Plate XXVII, is confined to the northern part 

 of New Mexico and the southern part of Colorado and Utah, and in 

 certain localities grows in very great abundance. Its aster-like 

 flowers are quite conspicuous, and the plant is readily distinguished 

 from other similar plants because of the dark golden-yellow color of 

 the flowers. The rubber plant has had a good deal of advertising 

 because it contains a certain amount of rubber and has been the 



