406 coMPOSiTJE. (composite family.) 



Suborder I. TUBUIilFIiOR^. Flowerets all tubular, or the marginal ones 

 only ligulate or strap-shaped. 



Fig. 233. 



(a) A head of the Tubuliflors cut across showing the involucre, the disk, and the disk- 

 flowerets, which are all tubular, except those at the marcin, these being strap-shaped, {b) 

 The same enlarged and stripped of all except one of the disk flowerets and two of the ray- 

 flowerets, (c) \ tubular floweret, with a toothed calyx and (d) a bristle at its base inserted 

 into the disk, (ee) Two of the ray -flowerets, with strap-shaped corollas. 



§ 1. Heads discoid. 

 * Flowers of the head all, or nearly all perfect. 

 t Pappus composed of awns, or tristles, or hairs. 

 I Pappus in one row or nearly so. 

 Receptacle naked. 



Scales few ------ Eupatorium 1 



Scales many, commonly colored - - Helichrysum 13 



Receptacle honey-combed - - - Varthemia 17 



Receptacle bristly - - - - Ptosimopappus 7 



Receptacle chaffy. 



Pappus in one row, short - - - Chrysophthalmum 24 



Pappus of 2-4 beards - - . - Bidens 29 



\ \ Pappus in tioo or more rows. 



Bristles of pappus united in a ring at base. 

 Receptacle thickly clothed with awns or bristles. 

 Pappus scabrous. 



Filaments free. Margins of scales unarmed - Carduus 58 



Filaments monadelphous. Margins of scales prickly. Silybum 64 

 Pappus feathery. 



A.kenes with apex more or less margined. 



