WEED FLORA OF IOWA 



Fig. 43. Smooth or Peach-leaved Dock (Rumex altissimus) , Dandelion (Taraxa- 

 cum officinale), and other weeds. This is where the seed comes from to 

 spread weeds. 



(Photographed by Charlotte M. King.) 



Extermination. — This weed has running roots and cannot be de- 

 stroyed in the same way as sour dock. The roots are, however, shal- 

 low, and can be destroyed by giving cultivation exposing the roots 

 to the sun. 



Bitter Dock (Rumex obtusifolius L.). 



Description. — A perennial herb, with roughish stem ; leaves some- 

 what wavy, the lowest ovate heart-shaped, obtuse, the upper oblong- 

 lanceolate, acute ; flowers inconspicuous, greenish on jointed pedi- 

 cels ; valves of the fruit conspicuous, toothed at the base. 



Distribution. — Naturalized from Europe ; eastern Canada to Wis- 

 consin, Minnesota and south to Texas and Florida. It is found in 

 waste places, sparingly introduced into Iowa with clover seed. 



Extermination. — The yellow spindle-shaped root is easily pulled 

 by giving the plant a slight twist, especially when the ground is 

 moist. Clover seed containing this weed should not be sown. 



