294 



WEED FLORA OF IOWA 



Fig. 168-A. Distribution of Toadflax. 



Extermination. — Fletcher and Clark recommend as follows : 

 "Short rotation of crops with deep, thorough cultivation in spring 

 and fall will suppress it. Hand-pulling when the soil is wet is 

 effective in pasture lands that cannot be cultivated. Badly in- 

 fested meadows or pasture lands should be brought under cultiva- 

 tion by plowing in July, summer-fallowing until autumn, and 

 planting with hoed crop the following spring." 



Simpson Honey Plant (Scrophidaria marilandica L.). 



Description. — A glabrous, somewhat glandular, pubescent peren- 

 nial, 3-5 ft. high; stems 4-angled; leaves thin, ovate, or ovate-lan- 

 ceolate, sharply serrate; flowers cymose; calyx lobes ovate, about 

 the length of the tube, corolla brownish purple; capsule subglob- 

 ular; seeds small, numerous. 



Distribution. — Common in woods and thickets from Maine 

 the Rocky mountains. Abundant in woods and adjacent fields. 



to 



Extermination.— Simpson honey plant produces a large number 

 of small seeds. However, but little is known of their vitality. The 

 weed is easily killed by cultivation and easily crowded out by 

 clover and small cereals. 



The Scrophidaria leporella Bicknell, is similar as regards the 

 foliage, the rudimentary stamen is, however, yellowish-green in- 

 stead of brownish-purple as in the S. marilandica. 



