(62) 



3. Matricaria. — Receptacle cylindrical, hol- 

 low. 



4. Baccharis. — Dioecious. 



b. Receptacle paleaceous or setaceous. 



aa, Branches of style connected near the 

 apex, 



1. Cnicus. — Receptacle densely bristly. 

 Bristles of the pappus plumose, con- 

 nected at the base into a deciduous ring. 

 Filaments of stamens distinct. 



2. Silybum. — Receptacle densely bristly. 

 Bristles of pappus not plumose, 1-seri- 

 ate. 



3. Oarthamus. — Pappus 0. 



4. Centaurea. — Receptacle densely bristly. 

 Bristles of pappus not connected at their 

 base into a ring. 



bb. Branches of style entirely distinct. 



1. Bidens. — Involucre 2-seriate, external 

 spreading, internal erect. Pappus of 

 2-4 awns. 



2. Madia. — Pappus 0. Receptacle some- 

 times only paleaceous near the ray and 

 naked at the disc. 



II. Superflua. 



A. Receptacle naked. 



a. Anthers obtuse at their base, at least not 

 calcarate. 



