348 



WEED FLORA OF IOWA 



Extermination. — This is a most troublesome weed in corn and 

 smaller grain fields of northern Iowa. The somewhat thickened 

 underground stems spread the plant freely by cultivation. The 

 small-grain field should be plowed after the grain is removed, 

 then dragged so as to expose the "roots" to the sun. Before 

 planting corn in the spring run a disk over the field, then har- 

 row, plant to corn, and give thorough cultivation. When the weed 

 is very bad it may be well to get the field into meadow or pas- 

 ture. 



Maximilian's Sunflower (Helianthus maximiliani Schrad.). 



Description. — Stem scabrous and hispid, 2-12 ft. high, the latter 

 height being obtained in alluvial bottoms ; leaves usually alternate, 

 thick, becoming rigid, scabrous above, hairy beneath, lanceolate, 



Fig. 203. Maximilian's Sunflower. (Helianthus maximiliani). Common in 

 meadows and fields of northern Iowa. Yellow flowers, hairy elongated 

 leaves. 



( Photographed by Colburn.) 



