452 



GRASSES OF IOWA 



in regard to the poisonous effects* of these plants. Chestnutf 

 has recently discuss-d the question and thinks that the 

 poison resides in a fungus that grows upon the leaves of the 

 goldenrod. In low lying meadows, especially along streams, 



Fig. 211. Muhlenberg's smart weed, {Polygonum viuhlenbergii). A trouble 

 some weed in low grounds. 



a large sunflower, the HeUanthus gross-seratus, is common, .some 

 times forming lar^e yellow masses. Where this sunflower 

 grows in large quantities, little forage is produced. In the 

 low-lying districts, especially swampy ground, smart weed 



*J L.Scott. Goldenrod Killing Horses. Garden and Forest. 8:477. 

 tPrellminary Catalogue of Plants Poisonous to Stock. Kep. Bur. of Animal In- 

 dustry. 15:393. 



