800 



COMPOSITAE (COMPOSITE FAMILY) 



like tips. Receptacle flat, alveolate. Achenes more or less flattened ; pappus 

 simple, of capillary bristles (double in 4 and 5). Perennial herbs (annual 

 only in 7 and 8), with corymbed, panicled, or racemose heads, flowering 

 chiefly in autumn. Kays white, purple, blue, or pink ; the disk yellow, often 

 changing to purple. Species often without sharply defined limits, freely hybrid- 

 izing. (Name dvrrip, a star, from the radiate heads of flowers. ) 



N.B. In this genus the heads are drawn on a scale of f, the leaves . 



A . At least the basal leaves cordate and definitely petioled B. 

 B. Stein-leaves petioled or sessile, not clasping G. 

 C. Kays white D. 

 D. Plant not glandular E. 

 E. Heads corymbose. 



Involucre ovoid-cam pan ulate, thick -cylindric, or turbinate; 



tufted basal leaves few or none. 

 Leaves thin, smoothish, at least not rough above 

 Leaves thick, rough above. 



Inflorescence slightly forking ; heads few, 1-1.5 cm. high 

 Inflorescence much branched; heads numerous, hardly 



1 cm. high 



Involucre slender, cylindric ; large tufted basal leaves abun- 

 dant 



E. Heads paniculate 



D. Glandular, at least as to the branches of the inflorescence . 

 C. Rays blue, or violet F. 

 F. Plant not glandular G. 



G. Involucral bracts with squrroase tips ; rays many (about 40) . 



G. Involucral bracts appressed or ascending ; rays fewer (10-20) H, 



H. Leaves entire or essentially so, firm, much longer than wide. 



Leaves harsh above ........ 



Leaves smooth above 



H. Leaves serrate, mostly thinner /. 



/. Involucre 4-6 mm. high ; bracts appressed, with conspicu- 

 ous colored tips ; heads abundant, paniculate. 

 Cordate leaves mostly on slender petioles, neither glau- 

 cous nor very smooth 



Cordate leaves mostly on winged petioles, glaucous be- 

 neath, smooth 



I. Involucre 6-10 mm. high ; bracts loose, without conspicu- 

 ously colored tips. 

 Heads abundant, densely racemo-paniculate. 



Stem essentially glabrous 



Stem densely short-pubescent 



Heads fewer, loosely paniculate or subcorymbose . 

 F. At least the branches of the inflorescence glandular 



E. Stem-leaves mostly cordate-clasping 



A. None of the leaves at once cordate and definitely petioled J. 



J. At least the lower leaves abruptly narrowed or constricted below 



the middle. 

 Leaves essentially entire, at most slightly constricted above the 



2. A. divaricatus. 



3. A.furcatus. 



4. A. glomeratus. 



5. A. Schreberi. 

 23. A. cordifolius. 



6. A. macrophyllu 



19. A. anomalus. 



20. A. azureus. 



21. A. Shortii. 



23. A. cordifolius. 



24. A. Lowrieanus. 



25. A. sagittifolius. 



26. A. Drummondii, 



27. A. Lin dley anus. 

 6. A. maerophyllus. 



22. A, undulatua. 



Leaves sharply serrate, the lower contracted to winged petioles. 

 Leaves with abruptly dilated auriculate-clasping bases 

 Leaves withoxit dilated bases, scarcely clasping .... 

 J. Leaves not abruptly narrowed or constricted below K. 

 K. Stem-leaves with cordate- or auriculate-clasping bases L. 

 L. Involucre glandular-hairy ; rays usually deep violet M. 

 M, Leaves conspicuously cordate-clasping, mostly entire. 



Branchlets glandular-viscid ; involucre hemispherical ; bracts 



subequal, linear-attenuate, loose 



Branchlets not glandular; involucre turbinate; bracts un- 

 equal, linear-oblong, with slightly spreading green tips . 

 M. Leaves obscurely cordate-clasping. 



Plant rigid, freely branching ; leaves mucronate-tipped ; in- 

 volucral bracts unequal, linear or linear-oblong, with 



spreading tips 



Plant not rigid, bearing few terminal heads; leaves thin, 



acuminate ; bracts equal, linear-attenuate 

 L. Involucre not glandular-hairy N'. 

 N. Bracts of the involucre distinctly imbricated, i.e. the outer 



series successively shorter O. 

 O. Plant smooth and glaucous. 



Leaves lanceolate to ovate ; heads paniculate 

 Leaves narrower ; heads solitary or racemose 

 O. Plant not glaucous. 



Tips of bracts squarrose or recurved-spreading. 



18. A. patens. 



48. A.prenanthoidt 

 47. A. tardiflorus. 



14. A.novae-angliae 

 18. A. patens. 



13. A. oblongifoli'us. 

 15. A. modestus. 



). A. laevis. 

 ). A. virgatus. 



