STOCK-POISOXIXG PLANTS OF THE RANGE 



69 



to be contagious, but it has been shown that it is produced by 

 A, heterophi/Uux. popularly known as rayless goldenrod or jimmy 

 weed. While the most serious effects of the weed in the Pecos Valley 

 have been on cattle, it will poison also horses and sheep. 



The plant (pi. 49) is a perennial, growing ordinarily to a height 

 of 2 feet, but it may reach 4 feet or more. It is very abundant in 

 some localities, frequently making a thick hedge along ditches. 



One of the most prominent symptoms is the muscular trembling 

 which has given rise to the name " trembles " as applied to the disease. 

 It has been shown that sometimes the offspring are poisoned by the 

 mother's milk. 



Xot only are calves poisoned by their mothers' milk, but it is 

 generally known in the Pecos Valley, where it has been a serious 

 handicap to the dairy business, that human beings may be affected 

 by the use of milk or butter from sick cows. 



Figure 32 shows a sheep poisoned by rayless goldenrod. The 

 animal trembled violently and could stand only a minute or two. In 

 Figure 33 is a steer in the last stages, shortly before death. 



It is important that stockmen should make certain that their ani- 

 mals get no large quantity of the plant. If animals are found eating 

 it they should be removed immediately to locations where there is 

 none. In the early stages of the disease they recover very quickly 

 if put on good pasture. 



The plant is rather easily destroyed by grubbing out to a depth of 

 2 or 3 inches, and thoroughly cleared pastures remain clear for a 

 long time. 



Another rayless goldenrod, A. fimticosus, found in southern Arizona, 

 produces the same 

 harmful effect as A. 

 heterophyllus. 



THE FERX FAMILY 

 (POLYPODIACEAE) 



BRACKEX <TTERIDIUM 

 AQUILINUM) 





— 



W ***** 



The common bracken 

 (pi. 50) should be 

 mentioned here as one 

 of the poisonous 

 plants, although the 

 losses from it are prob- 

 ably not large. It 

 has long been known 

 abroad that this fern 

 is poisonous to cattle 



and horses. There have been comparatively few reports in this 

 country of such losses, and those are largely confined to the North- 

 west, where the form is P. aqwilinum pubescens. There is no doubt 

 that bracken will poison both cattle and horses, and probably sheep, 

 and care should be taken that hungry animals do not have an oppor- 

 tunity to consume any large quantity. 



Figure 



A sheep poisoned by rayless goldenrod. 

 Aplopappus heterophyllus 



