162 COMPOSITE. 



III. ASTEROIDEJE. Style of the perfect flowers cylindrical ; its 

 branches linear, Jlattish on the outside, minutely and equally pubescent 

 above. 



11. ASTER. Linn. Aster. 

 (From the Greek a<mjp, a star ; which the flowers resemble.) 



Heads many-flowered ; the ray-flowers in a single series, ligu- 

 late, pistillate ; those of the disk tubular, perfect. Receptacle 

 flat, alveolate, or rarely naked. Scales of the involucre in many 

 series, more or less imbricated, with the tips sometimes foli- 

 aceous., Achenia usually compressed. Pappus simple, of nu- 

 merous rough bristles. 



* Scales appressed, nearly destitute of herbaceous tips. Bristles of the 

 pappus unequal. Achenia slender, scarcely compressed. Leaves large, 

 coarsely serrate, radical ones cordate. BIOTIA D. C. 



1. A macrophyllus Linn. : stem more or less hirsute above; leaves rough, 

 serrate, acuminate ; lower and radical on long petioles, cordate ; upper on 

 winged petioles or sessile, ovate ; heads in large corymbs ; scales of the in- 

 volucre oblong-lanceolate, obtuse. JDiotia macrophyU-a D. C. 



Woods. Can. to Geor. Aug., Sept. %.. Stem 23 feet high. Heads in a 

 spreading terminal corymb ; rays white or pale-blue. Large-leaved Aster. 



2. A. corymbosus Ait. : stem smooth, dichotomously corymbose at the 

 summit ; leaves ovate, mostly cordate, sharply serrate, acuminate, petiolate ; 

 heads loosely corymbose ; scales of the involucre imbricate, obtuse, shorter 

 than the disk ; outer ones ovate. Biotia corymbosa D. C. 



Dry woods. Can. to Car. July, Aug. 1\.. Stem about 2 feet high, some- 

 times purple, branched at the summit. Heads middle-sized, few, in a fastigiate 

 corymb ; rays white, narrow. Corymbed Aster. 



** Scales of the involucre ciliate, squarrose ; outer ones herbaceous. Re- 

 ceptacle alveolate. Bristles of the pappus rigid, unequal. Achenia hirsute, 

 rarely smooth. Leaves scabrous, mostly entire. Heads large and showy. 

 AMELLI Nees^. 



3. A. bifyorus Mich. : leaves sessile, narrow-lanceolate, serrate, scabrous; 

 stem one or few-flowered above ; scales of the involucre imbricate, ap- 

 pressed, oblong, acute, scarcely shorter than the disk. A. strictus Pursh. 



High mountains. Penn. Pursh. N. to Hudson's Bay and Labrador. Sept., 

 Oct. 7|.. Stem 4 6 inches high. Heads middle-sized ; rays pale violet ; disk 

 brownish-yellow. Few-flowered Aster. 



4. A. surculosus Mich. : stem simple, low and slender, minutely pubes- 

 cent ; lower leaves linear-lanceolate, entire or subserrate, scabrous above ; 

 upper linear, clasping ; corymb 3 5-flowered, somewhat naked ; involucre 

 imbricate, subsquarrose ; scales ciliate, linear-oblong, inner ones obtuse. 



Woods. N. S. ? S. to Car. Sept., Oct. 7J.. Stems several from the same 

 surculose caudex, 6 18 inches high, somewhat angled. Heads rather large ; 

 rays long, linear, violet. Perhaps not a native of the Northern States. 



Manif-ftemnwd Aster. 



