COMPOSITAE (COMPOSITE FAMILY) 



777 



Flowers purple 



Flowers whitish. 

 Involucral bracts much imbricated ; leaves chiefly 



opposite 



Involucral bracts little imbricated ; leaves alternate . 



of bristles e. 



'appus none or a mere crown-like margin to the fruit. 

 Heads 1-tlowered, themselves aggregated into globose glomerules; 

 leaves prickly .......... 



Heads many-flowered ; leaves not prickly. 

 Outer involucre foliaceous ; leaves opposite at least below . 

 Outer involucre not foliaceous ; leaves alternate. 



Receptacle conical, becoming elongated 



Receptacle flattish or merely convex. 

 Heads chiefly nodding, in spikes, racemes, or panicles . 



Heads corymbose 



6. Pappus present/. 

 /. Pappus composed of scales or chaff. 

 Receptacle naked. 



Leaves in whorls ' 



Leaves alternate. 



Leaves dissected 



Leaves entire 



Receptacle bearing chaff among the flowers. 



Leaves toothed or lobed , 



Leaves entire 



f. Pappus of 2-several teeth or awns. 



Pappus caducous .......... 



Pappus persistent. 



Achenes laterally compressed 



Achenes terete or flattened parallel with the involucral bracts. 

 Pappus barbed. 



Bracts of inner involucre connate to middle ; achenes terete 

 Bracts of inner involucre distinct or nearly so; achenes 



obcom pressed 



Pappus not barbed 



* * Flowers of two kinds in the same head g. 



. Marginal flowers neutral and sterile, either conspicuous or inconspicuous. 

 Leaves spiny ; heads subtended by foliaceous bracts .... 

 Leaves not spiny ; no conspicuous foliaceous bracts .... 

 . Marginal flowers pistillate and fertile 7t. 

 h. Receptacle chaffy. 



Receptacle awl-shaped ; achenes terete 



Receptacle flattish or moderately convex ; achenes flattened . 

 h. Receptacle naked or bearing no conspicuous chaff i. 

 i. Pappus of capillary bristles j. 

 j, Involu^>*al bracts imbricated in several rows. 



6. Trilisa. 



7. BrickelUa. 

 78. Cacalia. 



81. Echinops. 

 33. Polymnia. 



69. Matricaria . 



73. Artemisia. 



70. Chrysanthemum 



3. Sclerolepis. 



61. Hymenopappi 



62. Polypteris. 



65. Gaillardia. 

 58. Marshallia. 



Leaves toothed ; not woolly 

 Leaves entire ; plant more or less woolly. 

 Some flowers staminate and sterile . 

 All flowers fertile, either pistillate or perfect . 

 j. Involucral bracts chiefly in one row. 



Leaves cordate, triangular or palmately lobed 

 Leaves not cordate. 



Involucre carnpanulate 



Involucre ovoid at base, cylindric above . 

 i. Pappus a short crown or none. 



Achenes becoming much longer than the involucre 

 Achenes not exceeding the involucre. 



Heads corymbose, erect 



Heads solitary on long peduncles .... 

 Heads racemose or paniculate, nodding. 



10. Orindelia. 



53. Verbesina. 



55. Thelesperma. 



56. Bidens. 



54. Coreopsis. 



87. Cnicus. 

 86. Centaurea. 



27. Oifola. 

 51. Helianthus. 



26. Pluchea. 



29. Anaphalis. 



30. Gnaphalium. 



75. Petasites. 



23. Erigeron. 

 77. Erechtites. 



J. Adenocaulon. 



71. Tanacetum. 



72. Cotula. 



Lower leaves opposite 

 Lower leaves alternate 



39. Iva. 



73. Artemisia. 



* * * Staminate and pistillate flowers in separate heads k. 



fc. Pappus capillary. 



Leaves prickly ; heads large 



Leaves not prickly ; heads small. 

 Shrubs ; leaves mostly toothed ........ 



Herbs ; leaves entire. 



Pappus-bristles somewhat club-shaped in sterile flowers, but capil- 

 lary and slightly connate at base in the fertile 

 Pappus-bristles all capillary, not at all connate . 

 k. Pappus none ; fertile involucre becoming bur-like. 



Bracts of the staminate involucre united into a cup. 

 Fertile involucre armed with one ring of spines, teeth, or blunt 



83. Oirsium. 

 25. Baccharis. 



28. Antennaria. 



29. Anaphalis. 



40. 



