COMPOSITE. 409 



CoRYMBIFERS. 



k f Leaves opposite 6 



I Leaves alternate or radical *. . . . 7 



rFlower-heads small, numerous, purple. Pappus of many hairs. 



g ! 1. EUPATOBY. 



I Flower-heads few, rather large, yellow. Pappus of a few bristles. 



L 19. BlDENS. 



f Flower discoid, that is, all the florets of the head tubular or filiform, 



t- J the outer not longer than the central ones 8 



i Flowers radiate, the outer florets ligulate and spreading, or, if erect, 

 ^ longer than the central ones 18 



o f Achenes without a pappus, or crowned by a small cup or short scales . 9 



I Achenes bearing a pappus of hairs 12 



rFlower-heads monoecious, the males with many tubular florets, the fe- 



q J males forming a thick burr, ending in 2 conical beaks, and enclosing 2 



flowers 20. Burweed. 



^-Flower-heads all alike 10 



/-Receptacle bearing scales between the florets. Plant covered with a dense 



J white cotton. Leaves entire or toothed 13. Diotis. 



1 No scales between the florets. Leaves, at least the lower ones, much di- 

 L vided 11 



{Flower-heads hemispherical, 3 or 4 lines in diameter, in a large terminal 

 corymb. Achenes angular, with a flat top 14. Tansy. 

 Flower-heads small, often nodding, in a leafy raceme or panicle. Achenes 

 obovate, contracted at the top 15. Artemisia. 



r Bracts of the involucre linear, equal in length, with a few very small outer 



\2< ones 13 



I Bracts of the involucre imbricated in two or more rows 14 



r Radical leaves large, broadly heart-shaped or orbicular. Stem-leaves 



13 < small and narrow 2. Coltsfoot. 



L Leaves pinnate and toothed 17. Sekecto. 



^ Plants more or less covered with a white cotton or down. Involucral 



bracts also cottony, or shining and scarious, or coloured at the edge, 

 j 16. Cudweed. 



L Plants not woolly. Involucral bracts narrow and green 15 



r All the florets tubular and 5 -toothed 16 



15<j Outer florets of the head linear or filiform, although not longer than the 

 I central ones 17 



{Involucral bracts few, oblong-linear. Plant growing in salt-marshes. 

 3. Aster. 

 Involucral bracts numerous, narrow -linear. Plant growing on limestone 

 rocks 5. Linosyris. 



^Tall stiff plant. Flower-heads ovoid, in a terminal corymb. 



7. Rigid Inule. 

 { Flower-heads numerous and small, in a long leafy panicle. 

 L 4. Canadian Erigeron. 



r 



