DESCRIPTIVE MANUAL 



383 



Knapweed (Centaurea solstitialis L.). 



Description. — Annual erect, branched, cottony stem ; lower leaves 

 lyrate, deeply pinnatifid, upper leaves, linear, entire or nearly so, 

 de current wings on the stem; outer bracts, with long spreading 

 spines, those at base few and smaller; flowers yellow, with soft 

 pappus. 



Fig. 224. Knapweed, Star Thistle (Centaurea solstitialis). In alfalfa fields. 



(Mich. Agr. Exp. Sta.) 



