GRASSES OF IOWA. 



453 



{Polygonum muhleribergii) is common. This persistent perennial 

 with scarlet flowers produces very long, thick, stout root 

 stocks. It grows so thickly that grass is not produced. 

 Another weed which occurs in our low wild meadows is the 

 thistle (Cnicus ioivensis). This biennial weed makes very 

 little growth the first season, but the second season sends up 

 a large, much branched stalk and produces numerous purple 

 flowers. The allied bull thistle [Cnicus discolor) is especially 

 troublesome in pastures in the timber lot. It frequently grows 

 in such large masses as to becocce dtcidedly noxious. Stock 



Fig. 212. Common wild thistle, (Cnicus discolo?-). Common In meadows and woods. 



carefully weed around this plant, thus permitting its seed to 

 be sown broadcast in the field. Occasionally this weed may 

 be also found in meadows. 



The eastern ox-eye daisy {Chrysanthemum leucanthemum) is 

 as yet a rare plant in meadows or pastures of this state. This 

 perennial flowers during the early summer months. The large 

 white ray flowers are very conspicuous, and though a most 

 beautiful plant it is a most pernicious weed in the meadow. 



Another plant which has recently come into notice as a 

 troublesome weed is the rib plantain {Plantago lanceolata). 



