COMPOSITE. 



435 



scales of receptacle, disk-flowera 2- 

 sexual; style-arms not truncate. 

 Woolly herbs. 



Pappus-hairs simple . * 



Pappus-hairs plumose . • • 



Heads androgynous or homogamous ; 

 invol-'bracts scarioua and usually hya- 

 line, receptacle naked or pitted ; 

 flowers all fertile and with divided 

 styles ; style-arms of 2-3esual flowers 

 truncate. Hoary or woolly herbs • 



Hpads homogamous, discoid, arranged 

 in axillary clusters; invol-bracts 

 large, membranous ; flowers all fertile ; 

 receptacle with a few palese to the 

 outer flowers; style-arms short, 

 clavate ; pappus of 2 ovate scales 



Heads heterogamous, rayed (rarely sub- 

 discif orm ) ; flowers usually all fertile ; 

 receptacle naked or pitted ; style- 

 arms of 2-sexual flowers rounded or 

 dilated at the apex. 



Pappus in a single row . , • 



Pappus with an outer row of short 

 scales . 



16. FiLAGO. 



17. Ifloqa. 



18. Gnaphalium. 



19. C^SULIA. 



20. Inula. 



21. PULICAEIA. 



TRIBE v.— HELANTHOIDEai. Heads heterogamous, usually rayed, 

 or homogamous and rayless. Bay-floioers fem., fertile or neuter. 

 Disl-flowers 2-sexual, fertile or sterile. Eeceptacle paleaceous. 

 Anther-hases not tailed. Style-arms of disk-flowers truncate or 

 appendiculate, of the sterile flowers not divided. Achenes usually 

 angled. Fappus of 2-5 bristles, or paleaceous or 0. 



Heads monoecious (fem. and 2-sexual), 

 bisexual flowers sterile, with un- 

 divided styles ; fem. flowers apetalous ; 

 anthers nearly free, filaments 1-adel- 

 phous ; invol-bracts of fem. flowers 

 forming an ovoid 2-beaked utricle 

 covered with hooked spines ; pappus 

 0. Leaves alternate .... 



Heads heterogamous, rayed or discoid, 

 or homogamous and rayless ; ray- 

 flowers fem., fertile or sterile ; disk- 

 flowers 2-sexual or the innermost 

 rarely sterile ; receptacle paleaceous ; 



p2 



22. Xanthium^. 



