484 



COMPOSITE. 



Pappus-bristles (or some of them) plumose. 

 Receptacle naked. 



Achenes not beaked nor ribbed; tall annuals, paniculately branching 



above 3. Ptiloria, p. 491. 



Achenes (at least the inner) with a slender beak. 

 Flowers yellow; achenes 5 to 10-ribbed; low branching thistle-like 



biennial 4. Picris, p. 491. 



Flowers purple; achenes ribbed; perennial or biennial with grass-like 



leaves 5. Tragopogon, p. 492. 



Flowers white; achenes obscurelv ribbed; stem branching above; 



annual 6. Rafinesqtjia, p. 492. 



Receptacle with chaff -like bracts; at least the inner achenes beaked; 

 flowers yellow; stems naked; leaves radical . 7. Hypoch^ris, p. 493. 

 Pappus paleaceous, the paleaceous portion short or often very long, tipped 

 with a long or short bristle or awn which is either naked or barbellate, 

 or rarely subplumose. 

 Ligules short, the head in anthesis small; bracts of the involucre equal 

 but with shorter ones at base, all membranous; pappus-bristles 5. 

 Palese of the pappus elongated, cleft at tip, the short bristle or awn 

 proceeding from the cleft ; peduncle enlarged at summit ; heads erect. 



8. Uropappus, p. 493. 

 Palete of the pappus mostly short, abruptly or gradually passing into the 



awn ; peduncles not enlarged at summit; heads nodding in the bud. 



9. Microseris, p. 494. 

 Ligules elongated, the heads in anthesis showy; bracts of the involucre 



imbricated in several series; pappus-bristles 10 or more, barbellate or 

 subplumose, the paleaceous base short and firm 



10. SCORZOXELLA, p. 4%. 



B. Pappus of fine soft capillary bristles, scabrous but never plumose; 

 achenes ribbed or nerved. 



Achenes not flattened; receptacle naked, or bristly in some species of no. 11. 

 Achenes beakless; stems commonly branching or the plants acaulescent. 

 Pappus mostly soft and deciduous; achenes terete, truncate 



11. Malacothrix, p. 497. 

 Pappus dull white or tawny; achenes linear . . 12. Hieracium, p. 498. 

 Pappus white; achenes columnar or fusiform . . 13. Crepis, p. 499. 



Achenes with a slender beak; acaulescent plants, the peduncles 



1-flowered 14. Agoseris, p. 499. 



Achenes flattened; receptacle naked ; leafy-stemmed plants. 



Achenes beaked; heads in a panicle 15. Lactuca, p. 501. 



Achenes not beaked; beads eoryinbed or umbellate 16. Sonchtts, p. 501. 



Tribe 2. Cynareae. Thistle Tribe. 



Thistles or thistle-like herbs with alternate prickly leaves. Heads 

 large. Bracts of the involucre imbricated, usually prolonged into a 

 spine or bristle, or provided with a membranous edge. Receptacle 

 bristly or hairy. Flowers all perfect. Rays none. Corollas tubular, 

 cleft into long narrow lobes. Anthers long-tailed at the base, with 

 elongated appendages at the tip. Pappus bristly or plumose, rarely 

 paleaceous. 



A. Achenes obliquely or somewhat laterally inserted on the receptacle. 



Heads not leafy-involucrate ; pappus-bristles or -scales in 2 or 3 rows or 



none 17. Centaurea, p. 502. 



Heads leafy-involucrate; pappus-awns in 2 series . . .18. Cnicus, p. 503. 



B. Achenes inserted on the receptacle by their very base. 



Filaments distinct. 

 Pappus paleaceous and double (in 2 different sets). 19. Carthamus, p. 503. 

 Pappus of plumose bristles, united at base and deciduous in a ring. 



