COMPOSITAE (COMPOSITE FAMILY) 779 



Receptacle flat or nearly so. 



Achenes cylindrical, 2-awned 56. Theleaperma. 



Achenes flattened parallel to the chaff. 



Pappus-awns barbed 56. Bidens. 



Pappus-awns not barbed 54. Coreopsis. 



Jieceptacle 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. 



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

 Kays yellow to brownish-red or orange, neutral. 



Achenes 4-sided, inarginless 46. Jtudbeckia. 



Achenes flattened and margined 48. Lepachys. 



q. Rays pistillate and fertile r. 



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

 . Leaves alternate. 



Pappus of 1-3 awns or teeth 58. Verbei/na. 



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. Sorrichia. 



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 58. Verbesina. 



Achenes thickish 48. Hettopsis. 



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

 Achenes thickish, not strongly flattened. 



Inner bracts of the involucre not armed 88. Polymnia. 



Inner bracts of the involucre glochidiate, closely investing the 



achenes 84. Acantfiospermun*. 



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



Rays 5, obcordate, scarcely exceeding the disk, whitish . . 88. Parthenium. 

 Rays yellow, much longer than the disk. 



Achenes wing-margined, in several rows .... 85. Silphium. 

 Achene wingless, in a single row. 



Rays 5 ; leaves serrate 87. Chrysogonum. 



Rays usually more numerous ; leaves dentate or lyrately 



lobed 86. Eerlandiera. 



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



t. Pappus none. 



Leaves basal . . , . . . . 90. Arnoseris. 



Leafy-stemmed. 



Involucre calyculate ... 88. Lapsana. 



Involucre not calyculate 89. Serinia. 



t. Pappus wholly or in part of scales. 



Flowers blue, rose-colored, or rarely white 91. Cichorium. 



Flowers yellow 92. Krigia. 



t. Pappus bristle-formed, capillary u. 

 u. Bristles plumose. 

 Leaves basal. 

 Inner achenes long-beaked ........ 98. Hypochaeris. 



Inner achenes not beaked 94. Leontodon. 



Leafy-stemmed. 



Hispid-pubescent 95. Picris. 



Glabrous 96. Tragopogon. 



u. Bristles simple, at most scabrous . 



v. Achenes strongly muricate or cpinulose above. 



Leafy-stemmed 97. Chondrilla. 



Scapose 98. Taraxacum. 



V. Achenes not muricate above w. 

 V). Achenes flat or flattish. 



Achenes beakless ; flowers 50 or more in each head, yellow . 99. Sonchus. 

 Achenes mostly beaked ; heads 6-80-flowered ; flowers yellow, 



blue, or purple 100. Lactuca. 



?. Achenes columnar, often slender. 



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



Pappus white ; heads erect 101. Lygodesmia 



Pappus cream-color or tawny ; heads nodding .... 105. Pr&nanthea. 



