COMPOSITAE (COMPOSITE FAMILY) 779 



Receptacle flat or nearly so. 

 Achenes cylindrical, 2-awned ........ 56. Tfieleoperma. 



Achenes flattened parallel to the chaff. 



Pappus-awns barbed ......... 66. Sideng. 



Pappus-awns not barbed ........ 64. Coreopsis. 



Receptacle convex to columnar. 

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



Involucral bracts distinctly herbaceous. 

 Pappus of 2 awns. 



nppOMWM very deciduous ....... 61. BtUanthut. 



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



Pappus none or a crown of short teeth. 



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

 Rays yellow to brownish-red or orange, neutral. 

 Achenes 4-sided, margin less ....... 46. Rudbtckia. 



Achenes flattened and margined ...... 48. Lt.pa.ch.yn. 



q. Rays pistillate and fertile r. 

 f. Disk-flowers also fertile, their 



ir achenes maturing . 

 8. Leaves alternate. 



Pappus of 1-8 awns or teeth ....... 68. Verbesina. 



Pappus none. 



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

 Heads more than 1 cm. broad ; achenes not compressed . 63. Anthemia. 

 a. Leaves opposite. 



Maritime shrub .......... 60. SorricMa. 



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. Spilanth.es. 



Stout erect herbs. 

 Achenes laterally flattened ...... 58. Verbeina, 



Achenes thickish ........ 48. ffeliopsig. 



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. Acantfiogpermuin. 



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



Rays 6, 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. Chrynogonum. 



Rays usually more numerous ; leaves dentate or lyrately 



lobed .......... 86. Berlandiera. 



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



t. Pappus none. 



Leaves basal ......... ... 90. Arnoseria. 



Leafy-stfemmed. 

 Involucre calyculate . . . '. ...... 88. Lopxari'i. 



Involucre not calyculate ......... 89. Serinia. 



t. Pappus wholly or in part of scales. 



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



Flowers yellow ............ 92. frigid. 



t. Pappus bristle-formed, capillary u. 

 u. Bristles plumose. 

 . Leaves basal. 



Inner achenes long-beaked ........ 98. Hypochaeri*. 



Inner achenes not beaked ......... 94. Le&niodon. 



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. Chondritta. 



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. Sonchwt. 

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



blue, or purple .......... 100. Lactuca. 



v>. Achenes columnar, often slender. 



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

 Pappus white ; heads erect ....... 101. Lygodeamia 



Pappus cream-color or tawny ; heads nodding .... 105. I'renanthes. 



