484 COMPOSITE. 



Pappus-bristles (or some oJ them) plumose. 

 Receptacle naked. 

 Acnenes not beaked nor ribbed; tall annuals, paniculately branching 



abOTB 3. Ptilobia, p. 491. 



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

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



biennial i. PiCEIS, p. 491. 



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



leaves 5. Tbagopogon, p. 492. 



Flowers white; achenes obscurely ribbed; stem branching above; 



annual 6. Eafinesquia, p. 492. 



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



flowers yellow; stems naked; leaves radical . 7. HYPOCHa;Eis, 5. 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 barbeflate, 



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. 



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



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



8. TJKOPAPPDS, p. 493. 

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



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



9. MiCBOSEBIS, 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. SCOEZONELLA, p. 496. 



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. Malacothbix, p. 497. 

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

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

 Achenes with a slender beak; acaulescent plants, the peduncles 



1-flowered . . . .' 14. Agoseeis, p. 499. 



Achenes flattened ; receptacle naked ; leafy-stemmed plants. 



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



Achenes not beaked; heads corymhed or umbellate 16. SONCmjs, p. 501. 



Tribe 2. Cynarese. 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. Eeceptacle 

 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. Centaueea, p. 502. 



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



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



Filaments distinct. 

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

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



