184 CICHOKIACEAE 



1. C. IntybusL. CHICORY. Perennial, l-3 high, somewhat hairy: 

 leaves lanceolate, runcinate-pinnatifid, the stem leaves clasping : flowers 

 blue. Occasional in waste places in Kansas City and Independence. 

 July-September. 



2. TRAGOPOGON L. 



Involucral bracts in one series, subequal. Achenes ribbed, and long- 

 beaked, spinulose. 



1. T. porrifolius L. OYSTER PLANT. Biennial, 2-3 high: leaves 

 linear-lanceolate, entire : heads 2 / broad : involucre longer than the purple 

 rays. Rarely escaped from gardens in Independence ; also at Sheffield. 

 June-October. 



3. TARAXACUM Hall. 



Perennial herbs with yellow flowers solitary at the summit of hollow 

 scapes. Involucre double, the outer spreading, the inner erect. Achenes 

 angled and toothed, often spinulose above, long-beaked. 



1. T. officinale Weber. DANDELION. Leaves runcinate-pinnatifid, 

 oblong in outline : outer involucral bracts reflexed : achenes greenish- 

 brown. An abundant weed. April-June. 



4. SONCHUS L. Sow THISTLE. 



Ours are herbs with auriculate-clasping spiny-margined leaves and 

 corymbose-paniculate yellow heads of flowers. Involucral bracts imbri- 

 cated in several series Achenes oval to linear, flattened and ribbed. 



Involucre glandular-pubescent. 1. S. arvensis. 

 Involucre glabrous. 



Auricles of the leaves acute. 2. S. oleraceus. 



Auricles of the leaves rounded. 3. S. nsper. 



1. S. arvensis L. Perennial, l-3 high : leaves runcinate-pinnatifid : 

 heads 12 X/ high : achenes transversely wrinkled. Rarely adventized near 

 Sheffield. June-September. 



2. S. oleraceus L. Annual, l-5 high : leaves runcinate-pinnatifid : 

 heads 8 /x high ; achenes transversely wrinkled. Not uncommon in waste 

 places. June-September. 



3. S. asper (L. ) All. Annual, l-5 high : leaves from undivided to 

 pinnatifid, spinulosely dentate : heads 8 /x high : achenes not transversely 

 wrinkled. Common in waste places. June-September. 



5. LACTUCA L. WILD LETTUCE. 



Herbs with panicled heads of flowers. Involucre imbricated in several 

 series. Achenes oval to linear, narrowed above or beaked. 



Flowers yellow ; achenes long-beaked. 

 Leaves spiny margined. 



Heads 3 // -6 // high. 1. L. virosa. 



Heads 7 // -9 // high. 2. L. Ludoviciana. 



Leaves not spiny-margined. 



