The Flora of the Cayuga Lake Basin 403 



6. Aster (Tourn.) L. 



a. Leaves, at least the lower ones, cordate, petioled. 



b. Heads corymbose; involucral bracts, at least the outer ones, obtuse. 

 c. Involucre and pedicels pubescent but not glandular ; rays white. 

 d. Leaves thin, sharply toothed; involucre 4-6 mm. long. 1. A. divaricatus 

 d. Leaves thicker, shallowly toothed ; involucre 7-9 mm. long. 



2. A. Schrebcri 

 c. Involucre and pedicels minutely glandular-pubescent ; rays lavender, fre- 

 quently white. 3. A. macrophyllus 

 b. Heads paniculate; involucral bracts narrower, acute. 

 c. Leaves glabrous or sparingly villous, often rough. 

 d. Branches of the panicle strongly ascending ; rays white ; lower leaves 



ovate-lanceolate. 4. A. sogittifolius 



d. Branches of the panicle more spreading; rays normally blue or lavender; 

 leaves ovate. 

 c. Leaves thin, veiny, slightly scabrous above, prominently toothed, slightly 



or not at all wing-petioled. 5. A. cordifolius 



e. Leaves thicker, waxy, very smooth, less prominently toothed, mostly 

 wing-petioled, the upper ones more often sessile and more often tapering 

 at the base. 6. A. Lowrieanus 



c. Leaves velvety beneath, the upper ones broadly clasping, the lower ones with 

 wing-margined, dilated petioles, slightly toothed ; rays blue or lavender. 



7. A. undulatus 

 a. Leaves all sessile or tapering to a petiole-like base. 



b. Leaves clasping by a cordate base. 

 c. Plant glandular-pubescent; foliage fragrant when fresh; rays purple or rose. 



8. A. novae-angliac 

 c. Plant not glandular; rays normally blue or violet. 



d. Leaves not contracted below the middle and again dilated at base, serrate or 

 entire ; plants 6-25 dm. high, more or less strict. 

 e . Leaves waxy, very smooth and glaucous ; stem smooth and glaucous ; the 

 green tips of the involucral bracts rhomboidal ; rays bluish lavender. 



9. A. laevis 



e. Leaves not waxy nor glaucous ; the green tips of the involucral bracts 



narrow-linear ; rays blue. 



/. Internodes 10-60 mm. long, coarsely hairy over the whole surface, rarely 



glabrous ; leaves dull, scabrous above, more or less serrate ; panicle 



lax, coarsely hairy, rarely subvillous; heads with violet-blue rays and 



about 50 disk flowers; involucral bracts more spreading than in no. 11, 



and the tips more twisted and recurved; hairy part of style branches 



equaling the glabrous part. 10. A. puniceus 



f. Internodes, except the lowest, 5-13 mm. long, glabrous or somewhat 



villous on the angles ; leaves thicker, usually somewhat glossy, smooth 



except for the scabrous subentire margin, rarely sparingly scabrous 



above; panicle densely villous; heads with pale lilac rays and about 



35 disk flowers ; involucral bracts subappressed or spreading, rather 



straight ; hairy part of style branches shorter than the glabrous part. 



11. A. lucidulus 

 d. Leaves contracted below the middle and again dilated at base, strongly 

 serrate; plants about 7 dm. high, diffuse. 12. A. prenanthoidcs 



b. Leaves all without a cordate-clasping base. 

 c. Bracts of the involucre with green tips, the green midrib dilated toward the 

 apex. 

 d. Heads large, the involucre more than 5 mm. high; rays normally lavender 

 or blue; leaves linear. 13. A. junceus 



