YP Centaurea Le 
Annual branching herbs with alternate leaves, Heads discoid, their 
involucres subglobose or urn-shaped, consisting of several series of bracts 
which are closely appressed below the middle, spreading above, all more or 
less lacerate; flat, densely bristly. Corollas deeply S=cleft, the marginal 
ones enlarged, suggesting ray-flowers but funnel-shaped, commonly sterile, 
Pappus of 2-3 rows of short bristles, 
? Achenes notched just above the base, thus attached laterally 
/, Involucral bracts fimbriate, not spiny; flowers never yellow 
le C. Cyanus 
2 Involucral bracts spine-tipped; flowers yellow 2. Ce solstitialis 
Q Achenes not notched , attached basally; flowers blue Se C. repens 
le C. Cyanus Le Corn Flower, Bachelfor's Button, Herbs with slender 
branching stems which are more or less cobwebby; leaves linear, cobwe bby; : 
flowers verious shades of pink, blue or purple or white, the marginal ones 
commonly 15-16 mm, long; both inner and outer involucral bracts lacerate, 
In fields and waste places; naturalized from Europes 
2e Ce solstitialis L. Yellow Star Thistle. Leaves decurrent on the branches; 
bracts of the involucre terminating in rigid yellow spines as much as 2 om, long, 
In waste places; adventive from sa Europe 
Se Ce. repens L. ‘urkestan Thistle. Involucres longer than broad, the bracts 
unarmed, the flowers all similar, 
In waste places; adventive from ses Europe e 
