410 THE COMPOSITE FAMILY. 



r Achenes without any pappus, or crowned by a small cup or minute scales. 

 18 <{ 19 



LAchenes bearing a pappus of hairs 23 



r Receptacle bearing scales between the florets, at least among the central 

 19<^ ones 20 



L Receptacle naked (without scales between the florets) 21 



r Flower-heads rather large, with convex or conical receptacle. 

 20 < 11. Camomile. 



L Flower-heads small, with a small flat receptacle . . . 12. Achillea. 

 Q-. f Involucral bracts all green and of equal length 8. Daisy. 



I Involucral bracts imbricated and scarious at the edges 22 



22 J Receptacle flat or convex 9. Chrysanthemum. 



I Receptacle conical, much elongated as the fruit ripens 10. Matricary. 

 oo f R a y purple or blue 24 



I Ray yellow 25 



/-Involucral bracts and florets of the ray not numerous, oblong-linear. 



i 3. Aster. 



O 4 J 



j Involucral bracts and florets of the ray very numerous and narrow. 



L 4. Erigkeron. 



r Involucral bracts linear, equal in length, or with a few very small outer 



25 <{ ones 26 



L Involucral bracts imbricated in two or more rows 28 



f Radical leaves large, broadly heart-shaped or orbicular, distinct from the 

 j flowering stem. Florets of the ray narrow and very numerous. 



26 <J 2. Coltseoot. 

 I Radical leaves none, or at the base of the flowering stem. Florets of the 

 L ray linear or oblong 27 



2^ f Achenes of the ray without any pappus 18. Doronio. 



I Achenes of the ray with a pappus like those of the disk . 17. Senecto. 

 r Florets of the ray not more than 10 or 12. Anthers without tails. 



j 6. GOLDENROD. 



J Florets of the ray very numerous, or at any rate above 20. Anthers with 

 L minute fine points or tails at their base 7. Inule. 



Thistleheads. 



f Bracts of the involucre entire, obtuse or pointed, but not prickly . . 30 

 | Bracts of the involucre ending in a long, stiff point, hooked at the 



29 <j extremity 21. Burdock. 



' Bracts of the involucre prickly, or ending in a fringed or toothed ap- 

 pandage 33 



oq f Hairs of the pappus simple 31 



1 Hairs of the pappus feathery .32 



31 f Receptacle chaffy 22. Sawwort. 



I Receptacle naked 2. Coltsfoot. 



3 2 J Leaves entire or coarsely toothed, not prickly ... 23. Saussurea. 

 I Leaves either prickly or bordered with minute stiff bristles 24. Thistle. 



