STOCK-POISOXIXG PLANTS OF THE RAXGE 67 



New Mexico and Arizona, and in Mexico. The tips of the young 

 branches are sticky. The leaves are small, from one-eighth to three- 

 quarters of an inch long, and grow in dense clusters. The flowers 

 are in bell-shaped heads terminating the branchlets. The staminate 

 and pistillate flowers are on different plants. The white pappus of 

 the pistillate flowers makes the plants, when in blossom, conspicuous. 

 The plants may live at altitudes of from 4.000 to 7,600 feet, but are 

 more commonly found between 5.000 and 6,000 feet. 



There is good reason for thinking that this plant is responsible 

 for many losses of cattle from October to midwinter, at a time when 

 other forage is scarce. Experimental work has shown definitely that 

 it is poisonous to sheep, the toxic dose being about 1 pound for 

 a 100-pound sheep. Care should be taken that stock, especially 

 when poorly nourished, should not graze to any extent on this 

 plant. 



From what is known of B. ramulosa, it seems that it would not 

 be difficult to remove it from a range, as it is local in distribution 

 and easily destroyed by a mattock. 



PARRY ASTER (ASTER PARRYI) 



Parry aster, sometimes called Avoody aster, Aster pawyi (pi. 47), 

 occurs in great abundance in certain regions in Wyoming, and has 

 been accused of causing losses of sheep in those localities. There is 

 no doubt that the plant is poisonous. It is a fibrous plant, however, 

 and is very distasteful to sheep under ordinary circumstances, so 

 that there is very little danger from it provided the sheep are kept 

 in a region where sufficient feed is obtainable. 



COLORADO RUBBER WEED (ACTINEA RICHARDSONI) 



The Colorado rubber weed, or pingue, Actinea riclwrdsoni (pi. 48), 

 is confined to the northern part of Xew Mexico and southern 

 Colorado and Utah, and in certain localities grows in very great 

 abundance. Its asterlike flowers are conspicuous, and the plant is 

 readily distinguished from similar plants because of the dark golden- 

 yellow color of the flowers and a distinctive odor. The plant has 

 iiad a good deal of advertising because it contains a certain amount 

 of rubber and has been the subject of commercial exploitation. It is 

 said, especially in southern Colorado and northern Xew Mexico, that 

 sheep feeding on this plant late in the winter suffer severely. 



Experimental work has proved that the plant is poisonous to 

 sheep, but it has been found difficult, under corral conditions, to 

 make them eat it. Field observations have shown that in the lo- 

 calities where animals are reported to have suffered, the sheep in the 

 latter part of the winter are frequently kept under conditions closely 

 approaching starvation, and at such times, doubtless by force of 

 circumstances, they eat more of the plant. It is doubtful whether 

 there would be any loss from the plant if the sheep were properly fed. 



RAYLESS GOLDENROD (APLOPAPPUS HETEROPHYLLUS) 



In the Pecos Valley in Xew Mexico and Texas there has been for 

 many years a disease of animals, especially in cattle, known as milk 

 sickness, alkali disease, and trembles. For a time it was supposed 



