BUCKWHEAT FAMILY (POLYGONACEAE) 479 
Fic. 422. — A Smartweed (Polygonum Muhlenbergti), one of the trouble. 
some weeds, showing the sheathed nodes and terminal spikes of flowers ( x 3), 
and also showing a flower and a fruit much enlarged. This plant has bot 
underground and aérial stems. 
Fic. 423.—Field or Sheep Sorrel (Rumex Acetosella), showing the underground 
and aérial stems, the halberd-shaped leaves, and terminal spikes of flowers. X¥4. 
