SUMMARY 



(1) There are two common milkweeds in Nevada, both of which are 

 poisonous to sheep and cattle. 



(2) One is a slender, erect, branching weed with long, narrow, dark- 

 green leaves, small flowers, and slender pods. The other is a tall and 

 fleshy weed with large, broad, light-green leaves, coarse flowers, and 

 thick rough pods. 



(3) Both kinds grow in fairly moist places, along irrigation ditches, 

 by fences and on stream banks, on roadsides, and in patches in damp 

 pastures. 



(4) In the autumn the pods break open and release quantities of 

 flat brow r n seeds, each of which bears a tuft of shining silky hairs, 

 lighter than thistledown. The seeds are carried far by wind and water. 

 Once established, the plant spreads locally by means of its underground 

 stems. 



(5) Animals poisoned by the narrow-leaved milkweed become dull 

 and stupid within a few hours. They walk about with a wobbling, 

 unsteady gait, finally losing all control over the muscles of the legs, 

 and falling or lying down. After the animal is down, it has spasms 

 at short intervals in which the legs are extended rigidly. The heart 

 beats at an increasingly rapid rate ; the animal pants and grunts. The 

 head is drawn sharply back. The attack may last for twenty-four 

 hours and end with either the death or the recovery of the animal. If 

 it recovers, it will be in a weak and unsteady condition for several days. 



(6) Animals poisoned by the broad-leaved or showy milkweed stop 

 eating, grow dull, and lie down; the breathing is irregular, difficult, 

 and grunting. There are no spasms. The breathing becomes more 

 difficult, and the animals dies quietly. 



(7) The narrow-leaved milkweed is far more deadly than the broad - 

 leaved or showy species. 



(8) Two or three other milkweeds grow in Nevada; but they are 

 neither common enough nor poisonous enough to be of any importance. 



(9) When the narrow-leaved milkweed is accidentally cut and cured 

 in hay, it loses its bad flavor, but keeps its deadly character, thus 

 becoming far more dangerous than when fresh and green. Even the 

 dead and dried leaves, left standing in a field from the summer before, 

 are poisonous in midwinter. 



(10) It is a costly and difficult matter to get rid of the narrow-leaved 

 milkweed on even a small piece of ground. If a bit of the underground 

 stem is left in the soil, it will soon produce a new plant. 



(11) Both of our poisonous milkweeds have so unpleasant a flavor 

 that neither sheep nor cattle will eat them except when they are very 

 hungry and there is practically nothing else in the field for them to eat. 



(12) Poisoning may be prevented by keeping hungry animals and 

 animals in poor condition away from milkweed patches, and by stock- 

 ing pastures lightly enough to keep the animals constantly provided 

 with other food. 



