GRASSES OF IOWA. 



451 



spring up and take the p'ace of the better perennial species, 

 or the nadve ragweeds and verbenas spread and occupy the 

 soil. All of these have become so plentiful that iarmtrs 

 remark on their more frequent occurrence now than in former 

 years. Several rank-growing weeds are abuodaut in meadows 

 and pastures of western Iowa. Sunflower and Marsh Elder 

 find in the rich alluvial soil of the river bottoms a most con- 

 gt-nial place for their development. They are especially 

 troublesome on land that is often flooded during spring fresh- 

 ets. In addition to these the pastures throughout the state, 

 especially in the fall or autumn, are troubled with weeds like 

 Goldenrod. The large yellow flowered Goldenrod {Solidago 

 rigida) is extremely common in native pastures after the cattle 

 have been running all summer. Sometimes these pastures 

 present a mass of yellow. Then again the S. canadensis is 

 extremely common in similar situations Attention should be 

 called to this goldenrod since a few years ago there was con- 

 siderable discussion in veterinary papers and Garden and Forest 



Fig. 210. Wild sunflower, iHdiaiUhus urotse-serratus). Comnaon in low meadows. 



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