74 



PASTORAL AND AGRICULTURAL BOTANY 



congested. The' blood-vessels of the brain are congested, as well, as 

 those of the inner wall of the ileum. With horses the general symptoms 

 noticed are twitching of the surface muscles, constipation, dullness, and 

 a tendency when walking to lift the fore feet high. 



Stemless Loco Weed (Aragallus (Oxytropis) Lambertii}. This is a 

 perennial herb arising from a vertical thick, persistent tap root and with 

 radical, compound leaves with 11-17 narrowly lanceolate leaflets. The 

 racemes are erect, elongate and bear white to dark bluish-purple papilion- 

 aceous flowers succeeded by an erect, lance-oblong pod (Fig. 29). The 



PIG. 30. Map of the United States, showing the distribution of the stemless loco 

 weed. (Aragallus Lamberti). (After Farmers' Bulletin 380, 1909, p. 9, The Loco Weed 

 Disease.) 



plant is distributed over the plains region from Alberta and Assiniboia 

 in Canada south into Mexico, and from Minnesota and Kansas westward 

 to the Rocky mountains (Fig. 30). Plants bloom in Colorado in the latter 

 part of April. In parts of Colorado, Wyoming and Montana at the time 

 of flowering, large areas are as white as though covered with snow 

 (Fig. 31)- 



Wooly Loco Weed (Astragalus mollissimus) . This perennial herb is 

 frequently designated as "stemmed," because it has a leafy stem, which is 

 somewhat decumbent, bearing compound leaves with 23-29 leaflets 



