270 



WEED FLORA OF IOWA 



Fig. 155-B. Peppermint (Mentha piperita). In some gardens. 

 (Photographed by Colburn.) 



Carpenter Weed, Self-heal {Prunella vulgaris L.). 



Description. — A low, perennial weed with ovate-oblong, entire or 

 toothed leaves, hairy or smooth ; flowers collected in heads of 

 3-flowered clusters, corolla violet or flesh-color, or rarely pale in 

 color, longer than the purplish calyx which is tubular bell-shaped. 



Distribution. — Widely distributed in northern United States, 

 west across the continent in clay soils and woods, also from New- 

 foundland to Florida. 



Extermination'. — This weed is not difficult to exterminate by 

 giving cultivation with a cultivator and hoe. The weed is mainly 

 spread by seed. The seed of this is not uncommon in clover seed. 



