100 LXX. COMPOSITiE. 



Tribe 2. Eupatoriace.t:. (Gen. 7-10.) 



Leaves alternate. Pappus of 3-5 unequal scales . 7. Anisoch^ta, 

 Leaves o})posite. 



Heads many-flowered. 



Pappus of 5-10 broad, toothed, pointed scales 8. Ageratum, 

 Pappus of 3-5 gland-tipped bristles .... 9. Adenostemma. 

 Heads 4-flo\vered. Pappus of many slender 



bristles 10. Mikania. 



Tribe 3. Asteeoide.e. (Gen. 11-38.) 



1. Heads conspicuously radiate ; rays blue, pink 



or white (not yellow). 

 Receptacle covered with rigid paleae (chaff) . 12. Amellus. 

 Receptacle without p:deoe. 



Ray and disk-flowers both with bristle- 

 sliaped pappus. 

 Pappus-bristles plumose (feathered) . . 13. Maieea. 

 Pappus-bristles I'ough, but not feathered. 



Pappusuniform, of many similar bristles 17. Aster. 

 Pappus double, outer bristlesvery short 18. Diplopappus. 

 Ray-flowers without pappus ; disk-flowers 

 with bristle-shaped pappus. 

 Disk-flowers fertile, with well -feathered 



pappus 16. Charieis. 



Disk-flowers sterile, with serrated pappus 14. Gymnostephium. 

 All the flowers without pappus. Leaves 



pinnatifid • 21. Gaetjleum. 



2. Heads conspicuously radiate ; rays yellow. 



Receptacle nude, smooth or minutely rough. 



Pappus well-feathered (plumose) . . . .13. Maieea. 

 Pappus bristle-shaped, rough, in ono row\ 



Anthers not tailed at base 20. Nidoeella. 



Anthers tailed at base 33. Inula. 



Pappus bristle-shaped, in many rows, 



copious 11. Alciope. * 



Pappus double ; outer of short scales, inner 



of bristles 34. Pulicaeia. 



Pappus none -.,-.. 15. Anagltpua. 



Receptacle conspicuously honeycombed or 

 fimbrilliferous. 

 Rays neuter, with glabrous, abortive ovaries 36. Cypselodoxtia. 

 Rays female ; all the achenes hairy. Pap- 

 pus double. 

 Pappus of several-toothed bristles, outer 



shorter 37. Minueotkamnus. 



Pappus of broad scales, all or half of 



them awned 38. Geigeeia. 



3. Heads heterogamous, either discoid or very im- 



perfectly radiate ; the margin flower fe- 

 male, filiform, or with very sliort unilabiate 

 or bilabiate corollas (imperfect rays). 



Pappus double; outer of short scales, inner 



of bristles 3 k Pui.lCAEiA. 



Pappus single, of few or many slender bristles. 

 Margin-flower imperfectly ligulate (unila- 

 biate). 



