38 BULLETIN 



Experiments on sheep with the plant gathered in Utah produced 

 acute cases of poisoning but without loco symptoms. 



NONTOXIC PLANTS SUSPECTED OF BEING LOCOES 



Four plants popularly thought to be locoes have been shown to be 

 harmless. These plants, Oxytropis besseyi, Astragalus drummondii, 

 A. striatum, and A. bigelovii, are briefly described, with illustrations. 



Red Point Milk Vetch (Oxytropis besseti) 



Plate 26 shows a picture of Oxytropis) besseyi. This is a legu- 

 minous plant, rather common in the Yellowstone Valley, which is very 

 closely allied to the white loco weed and is frequently mistaken for it. 

 The flowers are of a deep-pink color, and the plant, while it grows in 

 the same regions as the white loco weed, is found upon the arid barren 

 summits of hills, the white loco growing most abundantly at slightly 

 lower levels. The two plants intermingle to some extent, but after a 

 little experience one is able to distinguish between them, as there 

 are certain noticeable differences in the leaves. Oxytropis besseyi is 

 known in Montana sometimes as the red loco, because of the color 

 of the flowers. Although the plant is closely related to the white 

 loco and grows in the same regions, there is abundant experimental 

 evidence that it is harmless. It should not be considered as a loco 

 plant. 



Drummond Milk Vetch (Astragalus drummondii) 



In Plate 27 is given a picture of Astragalus^ drummondii, which 

 occurs in many regions in connection with the white loco weed and is 

 frequently considered a loco plant. The plant is readily recognized 

 by its coarse stems and yellowish flowers, both the flowers and pods 

 being somewhat dependent. Many people consider this a dangerous 

 plant, but many experiments by the Department of Agriculture have 

 shown that it is entirety harmless and need not be feared. In general 

 appearance A. drummondii resembles the two-groove poison vetch 

 but is readily distinguished by the color of the flowers and by the 

 pods, which are one grooved instead of two grooved. 



Clover Milk Vetch (Astragalus striates) 



Astragalus striatus (pi. 28), in former publications called A. niti- 

 dus, is widely distributed and is abundant in the foothill region of 

 the eastern slope of the Kocky Mountains, frequently growing with 

 the white loco weed. Its leaves are deep green and its flowers 

 purplish and in compact heads like clover. It has been called a loco, 

 but has been shown to be harmless. 



Bigelow Milk Vetch (Astragalus bigelovii) 



Bigelow milk vetch (pi. 29) has long been considered one of the im- 

 portant loco plants of the Southwest. It is found from southwestern 

 Texas to Arizona and in Mexico. It resembles the purple loco weed 

 but is a larger and coarser plant, with more conspicuous flowers and 

 with densely woolly pods, while the pods of the purple loco weed are 

 smooth and dark brown or black. Because of this resemblance to the 

 purple loco it is sometimes called the Texas loco or woolly loco. Ex- 

 perimental feedings indicate that the plant should not be classed as a 



