STOCK-POISONING PLANTS OF THE RANGE. “5 
of white loco. The corolla, however, is frequently streaked with 
purple; sometimes the calyx is red; and sometimes, particularly in 
mountain regions, the whole corolla may be of a deep violet or purple 
color. All gradations in color may be found between these extremes. 
When the plants are in fruit the pods rattle as one hits them in walk- 
ing, very closely imitating the rattle of a rattlesnake, hence the name 
‘““rattle-weed.”’ 
Plate I is a picture of the white loco as found in the plains of Colo- 
rado. Plate II shows a field of the plant in blossom. The latter 
picture was taken in the Yellowstone Valley of Montana, but it- 
could easily be duplicated in Wyoming or Colorado. 
It is evident that where the plant occurs in these great numbers 
such a thing as eradication is impossible except by plowing over the 
whole country. If animals are turned loose in such a region as this 
they certainly will have an opportunity to obtain an abundance of 
loco. 
ASTRAGALUS DRUMMONDI. 
In Plate III is given a picture of Astragalus drummondi, which 
occurs in many regions in connection with the white loco and is fre- 
quently 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 extensive experiments by the Department of Agriculture 
have shown that it is entirely harmless and need not befeared. The 
picture is given here only that stockmen may be able to recognize it 
as a plant which need not be avoided. 
OXYTROPIS BESSEYI. 
Plate IV shows a picture of Oxytropis besseyi. This is a leguminous 
plant, rather common in the Yellowstone Valley, which is very 
closely allied to the white loco 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, 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 itis harmless. It should not be considered as a loco 
plant. The writer considers that the term ‘‘loco”’ should be applied 
only to such leguminous plants as have been proved to have poison- 
ous properties. 
