268 



WEED FLORA OF IOWA 



Fig. 154-A. Distribution -of Prostrate Vervain. 



with large bracts, small, purple ; triclionies few-celled from a broad 

 several-celled base. 



Distribution. — Common in waste places, roadsides, walks, gravel- 

 ly and sandy fields from Virginia to Wisconsin and Minnesota and 

 southward. 



Extermination. — It is easily exterminated by cultivation. 



LABIATAE, MINT FAMILY. 



The common pepperment, scarlet sage, catnip, pennyroyal, thyme 

 and basil belong to this family. All are aromatic plants. 



Mint {Mentha arvensis L.). 



Desdpption. — This perennial weed has freely branching stems 

 1-1% ft. high, retrorsely pubescent, leaves oblong to ovate, rounded 

 at the base, minutely pubescent, closely serrate, petioled or nearly 

 sessile ;■ flowers white, pink or violet. The varity canadensis has 

 lanceolate to oblong-lanceolate, pubescent leaves and is the common 

 form in Iowa in low grounds. Several other species occur in Iowa, 

 namely: peppermint {Mentha piperita) along brooks, a smooth 

 and pungent-tasting herb with ovate-oblong leaves and running 

 root-stocks, and spearmint {Mentha spicata) with oblong or ovate- 

 lanceolate unequally-serrate leaves. 



Distribution. — This Eurasian species occurs from Newfoundland 

 to Nebraska and the Pacific coast. 



ExtemmMiion. — Easily exterminated by giving thorough culti- 

 vation and dragging the soil to bring the root-stocks to the surface 

 of the ground. 



