COMPOSITJE. 188 



9. ASTER. 



Ray flowers pistillate, in 1 row, disk-flowers perfect, scales 

 imbricated, often with green tips; receptacle flat, alveolate; 

 pappus simple, capillary, scabrous ; achenium usually com- 

 pressed. 



Gr. ao'TnQ, a star; from its radiated flowers. A large genus of perennial 

 (one species annual) herbs with alternate leaves, very abundant in the United 

 States, blossoming in late summer and autumn. Invol. oblong, imbricate, the 

 inner scales loose, the outer spreading. Disk fls. tubular, regular, yellow, 

 changing to purple; ray fls. generally few (6 — 100), oblong, ligulale, '3-tooth- 

 ed, finally revolute, blue, purple or white, never yellow. 



§ Lower leaves cordate, petiolate. * Heads corymbose. 



1. A. CORYMBO'SUS. £it. Eurybia corymbosa. Cass. 



Stem corymbose-fastigiate, smooth; branches hairy, leaves ovate, acutely 

 serrate, acuminate, the lower ones cordate, petiolate ; petioles naked ; involucre 

 oblong, imbricate with closely appressed, obtuse scales. Common in dry 

 woods. Stem two feet high, smooth, often reddish, more or less flexuous. 

 Leaves large, mostly smooth, lower ones cordate-acuminate, with sharp 

 serratures, middle ones ovate, upper ones becoming lanceolate. Flowers in a 

 broad, flat-topped corymb, large, very open, with about G long, narrow, white 

 rays. Aug. Corymbcd Aster. 



2. A. MACROPHy'LLUS. Willd. Eurybia macropoylla. Cass. 



SZe?ra branched, diffuse; /eaces ovate, petiolate, serrate, rough, upper ones 

 ovate-cordate, sessile, lower ones cordate, petiolate; petioles somewhat wing- 

 ed ; im^uli/crc cylindric, closely imbricate with oblong, acute scales. Distin- 

 guished for its very large root leaves which are 6 — 10 inches long and 3 — 5 

 wide. Grows in woods. Stem furrowed, 1 — 2 feet iiigh. Leaves nearly 

 gmooth. Flowers rather large, white or pale blue. Sept. Large-leaved Aster, 



§ Lower leaves cordate, petiolate. * * Heads paniculate, 



3. A. cordifo'lius. 



Stem paniculate, smoothish ; loiper leaves cordate, hairy beneath, sharply 

 serrate, acuminate, petiolate ; petioles winged ; involucre closely imbricate, 

 the scales with short, green tips. Common in rocky woods. Stem smooth 

 below, more or less pubescent above, a little flexuous, striate, 2 feet high, 

 with a handsome panicle of racemes at top of numerous, rather small flowers. 

 Rays 10 — 15, pale blue varying to white. Lower leaves large, cordate, with 

 a deep sinus at base, the serratures very acute, the summit ending in a long, 

 acute point, slightly rough above, hairy and paler beneath. Petioles more or 

 less winged, hairy. Above, the leaves aie gradually reduced to small or 

 minute bracts. Sept. Heart-leaved Aster. 



4. A. sagittifo'lius. 



Stem with racemose branches above, smooth ; leaves oblong-lanceolate, 

 acuminate, sessile, serrate in the middle, radical ones ovate, oblong, cordate- 

 Bagittate, serrate, petiolate ; involucre scales loose, lanceolate. Found in rocky 

 woods. Stem 2--4 feet high, dividing into many ascending, rigid branches, 

 with numerous and crowded heads, t()rming a compound panicle of racemes. 

 Heads small, each with about 12 rays which are while or with various shades 

 of blue. Leaves becoming smaller above, lanceolate and even linear. Sept 

 Oct. Arrqw-leaved Aster. 



