160 SUMMER FLOWERS. 



32. Dipsacaceous Plants. DIPSACACE^:. 



(143) Dipsacus scales of the receptacle between the florets 



prickly or spinous. 



(144) Scabiosa scales of the receptacle between the florets not 



prickly or changed to hairs. 



33. Composite Plants. COMPOSITE. 



* Florets all tubular, or those of tlie disk or centre tubular 

 with the outer ones ligulate forming a ray, or slender and 

 filiform,; style of the perfect florets not swollen below its 

 branches (Corymbiferae). 



f Pappus none, or consisting merely of a border or short 

 scales or teeth. 



{ Receptacle scaly ; (pappus none). 



(145) An.th.emis heads radiant ; receptacle convex or conical ; 



involucre imbricated, of few rows; fruit terete, or ob- 

 tusely tetragonal, with a more or less prominent margin. 



(146) AcMLLea heads radiant; tube of the disk-florets piano- 



compressed, two-winged ; receptacle narrow, slightly ele- 

 vated ; involucre ovate or oblong, imbricated ; fruit com- 

 pressed. 



JJ Receptacle without scales ; (heads radiant). 



(147) Chrysanthemum involucre hemispherical ; receptacle 



plane or convex ; fruit terete, without wings or slightly 

 angular and somewhat winged ; pappus none, or consist- 

 ing of three minute teeth or an elevated border. 



(148) Matricaria involucre nearly flat ; receptacle elongate-co- 



nical ; fruit angular, not winged ; pappus none. 



ff Pappus of two or three persistent aivns. 



(149) Bidens heads discoidal, sometimes radiant ; receptacle flat ; 



involucre of two rows, the outer spreading; fruit com- 

 pressed, angular, rough at the edges. 



