722 



WEED FLORA OP IOWA 



Dr. Gray, in the above list mentioned 86 weeds which are more 

 or less aggressive in the Atlantic United States. It would seem, 

 however, that comparatively few of the aggressive weeds of the 

 Gulf states are enumerated in the list. The more important gulf 

 coast weeds are sneezeweed {Helenium tenuifoUum) , Louisiana ear- 

 pet grass {Paspahim platycaule), Johnson grass {Sorghum hale- 

 peTise), beard grass (Andropogon virginicum) , buffalo bur {Sola- 

 rium rostratum), prickly sida {Sida spinosa), southern nut grass 

 {Gyperus rotundus), wild pansy {Viola arvensis). Dr. Mohr gives 

 the following list of weeds as the most conspicuous by their 

 abundance all over the state of Alabama. 



Fio. 549. Johnson Grass (Sorghum halepense). An African weed. 

 In the Gulf states, and reported from southwestern Iowa. 

 (Lamson-Scrlbner, U. S. Dept. Agr.) 



Common 



