COMPOSITAE (COMPOSITE FAMILY) 



779 



Receptacle flat or nearly so. 

 Achenes cylindrical, 2-awned ........ 55. Thelesperma. 



Achenes flattened parallel to the chaff. 

 Pappus-awns barbed ......... 56. Bidens. 



Pappus-awns not barbed ........ 54. Coreopsis. 



Receptacle convex to columnar. 

 Involucral bracts with thin scarious margins . . . .68. Anthemis. 



Involucral bracts distinctly herbaceous. 

 Pappus of 2 awns. 

 Pappus-awns very deciduous ....... 51. Helianthus. 



Pappus-awns persistent . . ...... 52. Actinomeris. 



Pappus none or a crown of short teeth. 

 Rays rose-color (rarely yellow), pistillate . . . .47. Srauneria. 



Rays yellow to brownish-red or orange, neutral. 

 Achenes 4-sided, marginless ....... 46. Rudbeckia. 



Achenes flattened and margined ...... 48. Lepachys. 



q. Rays pistillate and fertile r. 



r. Disk-flowers also fertile, their achenes maturing . 

 8. Leaves alternate. 



Pappus of 1-3 awns or teeth ....... 53. Verbesina. 



Pappus none. 



Heads less than 1 cm. broad ; achenes obcompressed . . 67. Achillea. 

 Heads more than 1 cm. broad ; achenes not compressed . 68. Anthemis. 

 8. Leaves opposite. 



Maritime shrub . . . . ' . ..... 50. Borrichia. 



Herbs. 

 Annual, with white rays ........ 44. Eclipta. 



Perennial, with yellow rays. 

 Outer involucre of 4 connate bracts ..... 45. Tetragonotheca. 



Outer involucral bracts not connate. 

 Weak creeping herb ........ 49. Spilanthes. 



Stout erect herbs. 

 Achenes laterally flattened ...... 53. Verbesina. 



Achenes thickish ........ 43. Heliopsis. 



r. Disk-flowers not maturing achenes ; disk chaffy. 

 Achenes thickish, not strongly flattened. 

 Inner bracts of the involucre not armed ..... 33. Polymnia. 



Inner bracts of the involucre glochidiate, closely investing the 



achenes ........... 34. Acanthospermun'. 



Achenes flattened dorsally, i.e. parallel with the chaff. 



Rays 5, obcordate, scarcely exceeding the disk, whitish . . 38. Parthenium. 

 Rays yellow, much longer than the disk. 

 Achenes wing-margined, in several rows . . . .35. Silphium. 



Achene wingless, in a single row. 

 Rays 5 ; leaves serrate ........ 87. Chrysogonum. 



Rays usually more numerous ; leaves dentate or lyrately 



lobed .......... 36. Berlandiera. 



SERIES II. ALL THE FLOWERS OF THE HEAD WITH STRAP-SHAPED COROLLA t. 



t. Pappus none. 

 Leaves basal 

 Leafy-stemmed. 



Involucre calyculate 



Involucre not calyculate 



Pappus wholly or in part of scales. 

 Flowers blue, rose-colo 



rose-colored, or rarely white 



Flowers yellow 



, Pappus bristle-formed, capillary u. 

 u. Bristles plumose. 

 Leaves basal. 



Inner achenes long-beaked 



Inner achenes not beaked 



Leafy-stemmed. 



Hispid-pubescent 



Glabrous 



u. Bristles simple, at most scabrous . 



v. Achenes strongly muricate or spinulose above. 



Leafy-stemmed 



Scapose 



v. Achenes not muricate above w. 

 w. Achenes flat or flattish. 



Achenes beakless ; flowers 50 or more in each head, yellow 

 Achenes mostly beaked ; heads 6-30-flowered ; flowers yello's 



blue, or purple 



ID. Achenes columnar, often slender. 



Flowers cream -color, white, rose-color, or purple. 



Pappus white ; heads erect 



Pappus cream-color or tawny ; heads nodding . 



90. Arnoseris. 



88. Lapsana. 



89. Serinia. 



91. Cichorium. 



92. Krigia. 



93. Hypoehaerift. 



94. Leontodon. 



95. Picris. 



96. Tragopogon. 



97. Chondrilla. 



98. Taraxacum. 



99. Sonchux. 

 100. Lac.tuca. 



101. Lygodesmia, 

 105. Prenanthes. 



