374 OHIO EXPERIMENT STATION: BULLETIN 175. 



384 Brown Knapweed (P) *Centaurea Jacea L. This is a perennial plant 

 of the genus, whose seeds are frequent in alfalfa seed. These seeds are light 

 colored and shining but without brush of pappus. 



385 Star Thistle (A) *Centauiea solstitialis L. This star thistle is a con- 

 spicuous plant with an array of long, straw-colored spines about the yellow 

 head, after the manner of true thistles. lhe stems are wing-angled, woolly, 

 1 to 2 feet high, with leaves very narrow or of narrow segments. The whole is 

 gra} T ish in color. Eradicated by uprooting. Seeds usually light-colored, 

 smooth and shining, 1-10 inch long, w T ith a light pappus longer than the seed; 

 occasionally there are dark seeds of mottled aspect without pappus "brush" in 

 the same .head. Present in alfalfa seed as attested by numerous specimens 

 received from alfalfa seedings iu Ohio. 



