BUCKWHEAT FAMILY (POLYGONACEAE) 



479 



FIG. 422. A Smartweed (Polygonum Muhlenbergii), one of the trouble- 

 some weeds, showing the sheathed nodes and terminal spikes of flowers ( X |), 

 and also showing a flower and a fruit much enlarged. This plant has both 

 underground and aerial stems. 



FIG. 423. Field or Sheep Sorrel (Rumex Acetosella), showing the underground 

 and aerial stems, the halberd-shaped leaves, and terminal spikes of flowers. X|. 



