COMPOSITiE 



155 



nate leaves, often decurrent, and large heads on long peduncles, the 

 rays sometimes wanting. 



1. H. autumnSle, L. Swamp Sunflowek. 



Perennial ; stem stout, 1-4 ft. high, glabrous or nearly so ; usually winged 



by the bases of the leaves running down the stem ; branched ; leaves oblong 



to lanceolate, sessile, sharp at the apex and harrowed to the base; heads 



numerous on long peduncles in a sort of loose corymb. River valleys, 



- Man.-Alta. 



34. TARAXACUM. Dandelion- 



Heads large, many-flowered, solitary on a naked hollow scape; 

 involucre an inner row of nearly equal, slightly united bracts and 

 several outer rows 

 of shorter separate 

 bracts reflexed at 

 maturity; recepta- 

 cle naked; pappus 

 of numerous per- 

 sistent bristles 

 borne on the elon- 

 gated beak of the 

 achene. Perennial 

 stemless herbs with 

 a rosette of pinnatifld leaves, springing from a strong tap-root. 



1. T. officinale, Weber. Common Dandelion. 



Leaves coarsely pinnatifid; pappus white; flowers yellow. A common 

 introduced weed, troublesome in lawns. 



. — Taraxacum officinale. 



35. AGOSERIS. False Dandelion. 



Heads large, many-flowered; bracts of the involucre in 2 or 3 rows; 

 pappus white, of unequal bristles. Stemless perennials with 

 tufted linear root leaves and large heads of yellow flowers solitary 

 on a naked scape. 



1. A. cuspidata, (Pursh.) Steud. 



Leaves elongated, linear to lanceolate, entire; scape 6-12 in. high; achene 

 without a beak. {Troximon cuspidatum, Pursh.) Prairies, Sask. and Alta. 



2. A. glluca, (Pursh.) Steud. 



Leaves entire to lancinate, wider than in the preceding; scape 6-18 in. 

 high; achene beaked. {Troximon glaucum, Purah.) Prairies, Man.-Alta. 



