166 cOxMPOSiT^. [Composita. 



Florets of the circumference very numerous. Disk-florets few. 



Involucral bracts scarious, often coloured 31. Gnaphalium. 



Involucral bracts herbaceous or subulate. 

 Anthers obtuse at the base (without tails). 



Florets of the circumference ligulate, though slender, 



short and erect 12. Erigeron. 



Florets of the circumference all tubular and filiform . . 13. Conyza. 

 Anthers with hair-like points (simple tails) at the base. 

 Flower-heads clustered or paniculate. Styles of the disk- 

 florets all bifid 14. Blumea. 



Flower-heads corymbose. Styles of the disk-florets often 



undivided 15. Pluchea. 



Pappus none, or verj^ short. 



Florets of the circumference few. Achenes obovate or rounded 



at the top. Erect herbs or uudershrubs 30. Artemisia. 



Florets of the circumference very numerous. Achenes flat or 

 concave at the top. Prostrate aunuals. 

 E-ecei^tacle very convex. 



Flower-heads racemose or paniculate. Style-branches in 



the disk- florets acute 9. Dichrocephala. 



Ilower-heads solitary. Style-branches in the disk obtuse 27. Grange a. 

 Recejitacle flat or nearly so. 



Florets of the circumference apetalous or nearly so. 



Flower-heads terminal 28. Cotula. 



llorets of the circumference with a corolla nearly as long 



as the style. Flower-heads leaf-opposed . .' . . ^ 29. Myriogyne. 



§ 8. Flower-heads monoecious, the males globular, many -flowered, discoid; the females 

 ^-flowered, with a prickly burr-like 2-celled involucre. 



Single genus 19. Xanthium. 



§ 4. Flower-heads heterogamous, radiating. 

 Leaves opposite. Receptacle paleaceous. 

 Pappus none. 



External involucral bracts linear-spathulate, spreading, glan- 

 dular ^ 21. Siegesbeckia. 



External involucral bracts ovate or oblong, not glandular. 



Disk-florets 4-toothed 20. Eclipta. 



Disk-florets 5 -toothed 23. Wollastonia. 



Pajipus a little fringed cup 22. AYedelia. 



Pajjpus of 1 to 3 slender deciduous awns 23. "VVollastonia. 



Pappus of 2 to 5 persistent retrorsely hispid stiff awns. Achenes 



long 24. BiDENS. 



Leaves alternate. Receptacle paleaceous. 



Pappus of 2 or 3 stiff persistent awns. Anthers without taUs. 



Achenes long 25. Glossogyne. 



Pappus of several short pointed scales or awns. Anthers with 



tails 18. Anisopappus. 



Leaves alternate. Receptacle naked. 

 Pappus none or very short. 



Achenes ending in a short beak. Flower-heads small ... 8. Lagenophora. 

 Achenes not beaked. 



Receptacle very convex. Pappus of very short scales or 



bristles 10. Boltonia. 



Receptacle flat or slightly convex. Pappus none, or a short 



ring or cup 26. Chrysanthemum. 



Pappus of numerous long hairs or capillary bristles. 



No bilabiate florets. Anthers obtuse at the base (stem leafy). 



Ray white or purple ' . 11. Aster. 



