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 acg,ulescent, 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 

 largie 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. 



Diitribution. — ^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. 



