184 CICHOKIACEAE 



1. C. IntybusL. Chicory. Perennial, 1°-3° high, somewhat hairy: 

 leaves lanceolate, luncinate-piunatifid, the stem leaves clasping : flowers 

 hlue. — Occasional in waste places in Kansas City and Independence. 

 July-September. 



2. TRAGOFOGON L. 



Involncral bracts in one series, subeqnal. 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. ofBcinale 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. ] . S. arvensis. 

 Involucre glabrous. 



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



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



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

 heads 12" high : achenes transversely wrinkled. — Rarely adventized near 

 Sheffield. June-September. 



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

 heads 8" 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" high : achenes not transversely 

 wrinkled. — Common in waste places. June-September. 



5. LACTXJCA 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. viroaa. 



Heads f'-W high. 2. h. Ludoviciana. 



Leaves not spiny -margined. 



