244 SYSTEMATIC BOTANY. 



petioles ; upper ones ovate or oblong, sessile, or on winged petioles ; heads 

 in large, flat corymbs ; rays 12-15, white or bluish ; involucre with oblong, 

 acute scales. In woods, 1-2 feet high. August-September, 



3. A. CORDIFOLIUS (Heart-leaved Aster). Stem erect, mostly smooth, 

 with many divaricate branches above ; leaves cordate, sharply serrate ; heads 

 racemed on the branches ; rays 10-15, P a le blue ; involucre-scales appressed, 

 with short green tips. In rocky woods, 2 feet high. 



4. A. UNDULATUS ( Variable Aster}. Pubescent and somewhat hairy ; 

 stem erect, panicled above ; lower leaves cordate, on winged petioles ; upper 

 ones ovate or ovate-lanceolate, undulate or slightly serrate, on short, broadly 

 margined petioles ; all somewhat rough above, pubescent beneath ; heads 

 solitary, in somewhat unilateral racemes, arranged in a terminal panicle ; 

 rays pale blue. In dry woods and thickets. August-September. 



5. A. PATENS (Spreading Aster}. Pubescent and somewhat rough ; stem 

 branching ; leaves oblong-ovate, or oblong, sessile, cordate, and clasping the 

 stem at base, rough above and on the margin, entire ; heads large, with very 

 showy violet-purple rays, solitary, on leafy branchlets, forming a loose, termi- 

 nal panicle ; involucre-scales lanceolate, with spreading, green tips ; achenia 

 silky. In dry fields, 2-3 feet high. August-October. 



6. A. L^EVIS (Smooth Aster). Very smooth and often glaucous ; stem 

 angular; leaves lanceolate, or ovate-lanceolate, somewhat fleshy, mostly 

 entire ; the upper ones somewhat cordate, or auriculate at base ; the lower 

 and radical ones tapering to a winged petiole ; involucre-scales with broad- 

 linear, appressed, green tips ; heads large at the ends of the branchlets, with 

 bright blue, showy rays, forming a terminal panicle. In low grounds, 2-3 

 feet high. September-November. 



7. A. PUNICEUS (Rough Aster). Stem erect, very branching, pubescent, 

 rough, paniculate above ; leaves lanceolate, auriculate, and clasping at base, 

 slightly serrate, pubescent ; heads large, with very numerous and narrow, 

 pale-purple rays, showy, forming a very large and leafy panicle ; involucre- 

 scales narrow-linear, long and revolute in 2 rows. Swamps and low grounds. 

 September- October. 



8. A. NOV^E ANGLIC (New England Aster}. Stem stout, hispid, pa- 

 niculate above ; leaves lanceolate, entire, acute, auriculate and clasping at 

 base, somewhat pubescent, thickly clothing the stem ; heads large, with 

 numerous, deep-purple rays, somewhat paniculately corymbose. In moist 

 grounds. September. 



9. A. TRADESCANTI (Narrow-leaved Aster). Nearly or quite smooth; 

 stem terete, with virgate, erect, spreading, or diverging branches ; leaves 

 linear-lanceolate, the lower ones commonly serrate in the middle, the others 

 entire ; heads very numerous, rather small, mostly with rays, densely race- 

 mose on the branches ; involucre-scales narrow-linear. In moist fields. 

 August-October. 



10. A. MULTIFLORUS (Many-lowered Aster}. Pubescent and some- 

 what rough ; stem very branching ; leaves linear, crowded on the stem, en- 

 tire, sessile, those of the branches much smaller ; heads small', with white 

 rays, very numerous, densely racemose on the spreading branches ; involucre- 



