142 WEED FLORA OP IOWA 



Prairie Larkspur {Delphinium .pena/rdi Huth.). 



Description. — A perennial, pubescent or hairy herb, more or less 

 glandular above, with simple, erect stem, 3-5 ft. high; leaves 3-5 

 parted, divisions 2-3 cleft; the numerous flowers white, or bluish- 

 white, in elongated raceme, spur ascending or erect ; follicle many- 

 seeded. 



Distribution. — From Illinois and Wisconsin, westward and north- 

 ward. Common on gravelly knolls along railroads throughout the 

 state of Iowa. 



Extermination. — This perennial is easily exterminated by culti- 

 vation. The roots of the plant readily succumb when exposed to 

 the sun. 



Pig. 80-B. Prairie JJarkspur (DelpMnlum penordi). Common on gravelly knolls. 

 (Drawing by Ada Hayden.) 



CRUCIFERAB, MUSTARD FAMILY. 



This family contains the well known sweet alyssum, cabbage, cauli- 

 flower, rape, radish, turnip, white and black mustard, water cress, 

 etc. They are all pungent herbs. 



