Jones: Flora of Illinois, 152. Compositae 243 



Series I. Tubuliflorae DC. 



1 . Pappus of capillary bustles. 



2. Heads radiate (i.e., the outer flowers of the head with strap-shaped corollas). 



3. Rays yellow (whitish in one species of Solidago). 



4. Bracts in one series, about equal in length (a few short basal ones sometimes 

 present) ; pappus single. 



5. Leaves opposite, dissected into linear lobes; bracts bearing 3-7 conspicuous 



glands; pappus of 8-15 scales, each dissected into 5-10 bristles 



38. Dvssodia 



5. Leaves alternate and basal; bracts glandless; pappus of numerous capillary 



bristles 47. Senecio 



4. Bracts in several series, very unequal, overlapping. 



6. Heads numerous, small; pappus single 12. Solidago 



6. Heads few, large, solitary, or corymbose. 



7. Leaves serrate, large; pappus single; stem 1-2 m. tall, usually simple 



19. Inula 



7. Leaves entire or nearly so; pappus double; stem 30-60 cm. tall, branched 



I 1 . Chnsopsis 



3. Rays not yellow. 



8. Bracts in 3-5 series; rays broad, few 14. Asler 



8. Bracts usually in 1 or 2 series; rays usually narrow and numerous 



15. Ertgeron 



2. Heads rayless (or apparently so), the flowers usually all tubular. 

 9. Flowers white or whitish, or cream-color. 

 10. Leaves pnckly. 



1 1 . Heads 1 -flowered, in capitate clusters 49. Echinops 



1 I. Heads many-flowered, distinct 50. Cirsium 



10. Leaves not prickly. 

 12. Bracts scarious. 



13. Leaves mostly basal, spatulate or obovate, the stem-leaves small; plants 

 perennial, sloloniferous, dioecious or polygamous 17. Anlenriaria 



13. Leaves all or mostly cauline; plants annual or biennial, not stolon- 



iferous or dioecious; all the flowers fertile, the central ones perfect, 



surrounded by pistillate ones 18. CnaphaliuTn 



12. Bracts not scarious. 



14. Bracts with tips hooke*! ; coarse biennial weeds with large ovale 



leaves; heads globose 48. Arctium 



14. Bracts not hooked. 



15. Principal bracts in only one series (often with a few small bractlels 

 at the base of the head). 

 16. Pappus scabrous; flowers all perfect; plants perennial, with 

 milky sap 45. Cacalia 



16. Pappus smooth; marginal flowers pistillate, the disk-flowers 



perfect; plants annual, with watery sap and strong odor 



46. Erechtiles 



15. Bracts in more than one series. 



17. Leaves all or mostly opposite or whorled (or some of the upper 



ones alternate) 6, Eupaiorium 



17. Leaves alternate. 



18. Bracts striate, imbricated in 3 or more equal series; pappus 

 plumose; achenes striate, nearly terete; leaves minutely 



resinous-dotted 8. Kuhnia 



18. Bracts not striate, in 1-3 series; achenes flattened; pappus 

 merely scabrous; leaves not resinous-dotted. 

 19. Heads racemose; outer bracts foliaceous; pappus copi- 



ious, of soft bristles; achenes terete 



species of 14. Aster 



