334 CARDUACEAE. 



Achenes s-io-ribbed. 



Bracts of the involucre erect, not spreading nor reflexed. 



Involucres many-flowered ; pappus present ; achenes tapering below. 



Bracts of the involucres nearly equal and similar, all distinct. 



Leaves simple ; stem scapiform or with a few small leaves ; 



heads long-peduncled. 

 Corollas yellow ; bracts numerous ; leaves linear to oblong. 



67. TETRANEURIS. 



Corollas flesh-colored; bracts about 12; leaf-blades from 

 orbicular to oblong. 68. CHAMAECHAENACTIS. 



Leaves dissected into linear lobes ; stem low but leafy. 



69. RYDBERGIA. 



Bracts of the involucres unequal ; the outer united at the base. 



70. HYMENOXYS. 

 Involucres few-flowered; pappus wanting; achenes linear, 8-10- 



striate. 71. FLAVERIA. 



Bracts of the involucres spreading or reflexed. 



Leaves not decurrent on the stem ; tubes of the disk-flowers 



moderately long. 72. DUGALDIA. 



Leaves decurrent on the stem ; tubes of the disk-corollas very 



short or reduced to a ring. 73. HELENIUM. 



2. Receptacle with bristle-like chaffs. 74. GAILLARDIA. 



B. Plant-tissues, especially the leaves and involucres with oil-glands ; plants 



heavy-scented. 

 Bracts of the involucres more or less united ; stigmas of the disk-flowers 



elongated. 

 Bracts of the involucres united only at the base ; stigmas with conical tips. 



75. BOEBERA. 

 Bracts of the involucres united into a cup ; stigmas obtuse. 



76. LOWELLIA. 



Bracts of the involucres distinct ; stigma very short, obtuse, without an 

 appendage. 77. PECTIS. 



TRIBE 7. ANTHEMIDEAE. 

 Receptacle chaffy. 



Achenes terete, at least not flattened ; involucres hemispherical, large. 



78. ANTHEMIS. 

 Achenes flattened ; involucres campanulate or obovoid, small. 



79. ACHILLEA. 

 Receptacle naked or merely pubescent. 



Heads radiate. 80. CHRYSANTHEMUM. 

 Heads discoid. 



Plants spiny; achenes and corollas cobwebby. 81. PICROTHAMNUS. 



Plants not spiny ; achenes not cobwebby. 82. ARTEMISIA. 



TRIBE 8. SENECIONEAE. 



Plants scapiferous, dioecious or nearly so, with large basal leaves appearing after 

 flowering ; hermaphrodite flowers usually sterile. 83. PETASITES. 



Plants not scapiferous, not dioecious ; disk -flowers hermaphrodite, fertile. 

 Involucres of many or several bracts. 



Involucres of commonly much overlapping or unequal bracts. 



84. HAPLOESTES. 

 Involucres of connivent erect herbaceous equal bracts, with or without 



smaller calyculate ones below. 

 Leaves mostly opposite ; pappus of a single series of rigid bristles. 



85. ARNICA. 

 Leaves alternate ; pappus of numerous soft bristles. 



86. SENECIO. 

 Involucres of 4-6, firm, concave, erect and strongly overlapping bracts ; shrubs 



with alternate leaves and discoid heads. 87. TETRADYMIA. 



