194 



WEED FLORA OF IOWA 



Fig. 111. Rattle-box (Astragalus canadensis) . Woodland pastures. 

 (Photographed by Charlotte M. King.) 



Purple or Stemless Loco Weed (Oxytropis lamberti Pursh.). 



Description.— Nearly acaulescent, perennial herbs or shrubby 

 plants, with tufts of very numerous short stems coming from a hard 

 and thick root-stock containing many scaly stipules ; stems and 

 leaves covered with silky and finely appressed hairs, or smoothish ; 

 leaves pinnate ; leaflets linear ; flowers racemose or spicate, rather 

 large and elongated, purple, violet, or sometimes white ; stamens dia- 

 delphous ; keel tipped with a sharp projecting point. This is one of 

 the loco weeds, poisonous to cattle. 



Distribution. — Western Minnesota, western Iowa, and Missouri to 

 Texas, and New Mexico, north to British Columbia, and northwest 

 territory. 



Extermination. — It seldom gives much trouble in cultivated fields. 



