352 COMPOSITAE. 



Pappus in one row. 

 Heads in panicles. 



Panicle thyrsoid ; re- 

 ceptacle alveolate. 504. Solidago, 364. 

 Panicle flat-topped; re- 

 ceptacle fimbrillate. SOS. Euthamia, 366. 

 Heads solitary or in cor- 

 ymbs. 

 Leaves all or mostly 



opposite. 538. Arnica, 384. 



Leaves alternate. 



Heads large, 1.5 cm. 

 or more 

 broad. 

 Heads 5 cm. or 



more broad. 544. Inula, 393. 



Heads less than 



3 cm. broad. 503. Hoorebekia, 363. 



Heads small, 1 cm. 



or less broad. 



Involucre cam- 



panulate. 539. Senecio, 386. 



Involucre hem- 

 ispheric or 

 broader. 

 Tegules 8- 



10, broad. 537. Crocidium, 383. 

 Tegules nu- 

 merous, 

 narrow. 506. Erigeron, 366. 



484. LAPSANA. Nipple-wort. 



Annuals with loosely branched leafy stems and milky juice; 

 heads 8-12-flowered; involucre narrowly cylindrical, consisting 

 of 8 principal tegules with smaller calyculate ones at the base; 

 flowers yellow; receptacle naked; akenes oblong-obovoid ; pappus 

 none. 



Lapsana communis L. Glabrous above, somewhat pubescent below; stem 

 erect, branched at top, 30-100 cm. high; leaves thin, the lower ovate, somewhat 

 dentate, petioled, often with 2-6 lobes, at base, the upper oblong to lanceolate, 

 acute, sessile, entire or subentire; heads numerous in a flat-topped inflores- 

 cence; involucre cylindric; principal tegules about 8, linear, 4-5 mm. long, with 

 several smaller ones at base. 



Common in waste places; introduced from Europe. 



485. TRAGOPOGON. 



Stout leafy-stemmed and usually branching biennials or per- 

 ennials, with milky juice; leaves entire, grass-like, clasping; 

 flowers yellow or purple, in large solitary heads; involucre simple, 

 of several equal bracts ; pappus of numerous long-plumose bristles ; 

 corollas all ligulate; akenes narrowly fusiform, 5-10-ribbed, 

 long-beaked. 



