408 



COMPOSITiE. (COMPOSITE FAMILY.) 



Marginal flowerets pistillate, central perfect. 

 Receptacle chaffy, at least at edge. 

 Pappus composed of scabrous bristles 



Pappus plumose 



Pappus none 



Pappus of 1-3 or 10 pales. Scales unarmed 

 Pappus of 8-10 pales. Scales spiny-tipped 

 Receptacle naked or covered with papillae or bristles. 

 Pappus composed of scabrous awns or bristles. 

 Plants with a woody base. 



Shrubs, 1 or more high ; leaves green ; heads 



corymbose 

 Herbs, .3 to. 5, growing in crevices of rocks ; 



heads solitary 

 Canescent herbs or small shrubs 

 Plants not woody at base - - - - 

 Pappus plumose. Dwarf desert plants 

 Pappus none. Plants shrubby at base - 

 Marginal flowerets pistillate, central staminate. 

 Pappus scabrous ; some of the akenes 2-horned 

 Pappus of bristles and pales . - . 



Pappus none. 



Outer flowerets in several rows ... 

 Outer flowerets in one row . _ . 



Marginal flowerets neutral, central perfect. 



Receptacle chaffy 



Receptacle clothed with fringed bristles. 

 Filaments free. 



Pappus composed of bristles united in a ring 



at base 

 Pappus composed of bristles not united at 



base 



Outer pappus bristles, inner connivent pales 



Outer pappus 10 awns, inner 10 bristles 



Outer pappus in oo rows of barbellate bristles, 



inner 5-10 pales 



Filaments monadelphous . - . ^ 



* * * Heads moncEcious. 

 Involucre of scales grown together, covered with 



hooked prickles 

 Involucre of unarmed heads not more than . 003 broad 



§ 2. Heads discoid or radiate. 

 Receptacle naked. 



Pappus hairy, about 1-rowed _ _ . 



Pappus hairy, in more than 1 row - - - 

 Pappus crown-like or 0. 



Annuals or perennials. Akenes obpyramidal, 

 Annuals, Fragrant. Akenes nearly terete, 



back smooth 

 Perennials. Akenes equally ribbed, prismatic 

 Receptacle chaffy. 

 Pappus consisting of plumose pales 



Conyza 



Atractylis 



55 



