PALATABILITY OF POISONOUS PLANTS 243 



The buttercup family (Ranunculaceae) embraces the larkspurs 

 (Delphinium) which cause such alarming losses among cattle. 

 There are many species of larkspur, a few of which are widely 

 distributed. 



The pea or pulse family (Leguminosae) , which, next to the 

 grass family, embraces the most economically important pasture 

 and range plants, also includes a number of species that are 

 highly poisonous to livestock. The most troublesome of these 

 are the loco weeds (Astragalus and Oxytropis). Lupines (Lu- 

 pinus) are also embraced in this family. 



The parsnip family (Umhelliferae), like the pea family, in- 

 cludes a large number of highly palatable and nutritious forage 

 plants, but it embraces toxic species also. Among these is in- 

 cluded water hemlock (Cicula) , one of the most deadly poisonous 

 plants in North America. 



Interspersed with species of the more common genera of 

 poisonous plants named are many genera whose species contain 

 toxic substances and are more or less troublesome to range live- 

 stock. 



In addition to the poisonous species of higher plants, only the 

 more prominent of which have been mentioned, powerfully 

 toxic substances occur among some of the bacteria and parasitic 

 fungi. Certain mushrooms and some smuts, like ergot, have 

 been the cause of livestock losses. Like many poisonous flower- 

 ing plants, the fungi are somewhat variable in the toxic sub- 

 stances present. 



Although something may be accomplished in the application 

 of medical remedies to poisoned animals on the range, the main 

 reliance in the control of losses must be upon better range man- 

 agement and improved livestock handling. 



Palatability of Poisonous Plants. — The fundamental rule 

 concerning the poisoning of any animal is that a certain amount 

 of the toxic plant substance must be absorbed and circulated by 

 the blood to cause death. The effect upon an animal that con- 

 sumes a poisonous plant, then, depends not only on the amount 

 devoured but on the rapidity with which the toxic substance is 

 eliminated. The latter varies with different plants and animals, 



