162 COMPOSITE. 



Sectiox 1. Heads radiate; rays cyanic. 



10. ASTER. Linn. Starwort. Aster. 



Gr. astro, a star; from the appearance of the radiate heads of flowera. 



Heads many-flowered; ray-flowers in a single series, fertile . ; 

 dish flowers tubular, perfect. Scales of the involucre 

 more or less imbricated, often with leaf-like tips. Recep- 

 tacle flat, alveolate (honey comb-like). Achenia usually 

 more or less flattened. Pappus simple, of capillary bris- 

 tles. — Perennial herbs, with alternate leaves, eorymbed, pani- 

 cled or racemose heads of flowers, with white blue or purple 

 rays, and yellow dish, often changing to pwrph. 



1. Biotia, DC. Scales Imbricated with oppressed greenish tip? : rays C to 15 (white 

 or nearly so); lower leaves large, heart-shaped, peiiolute ; heads in open corymbs. 



1. A. corymbosus, Ait. Corymbed Aster. 



Stem slender; !«nw ovate, mostly cordate, coarsely and unequally serrate, 

 acuminate, petioled; heads loosely corymbose: rays 6 to 9. 



Dry woods; common. July. Aug. Stem 1 to 2 foet high. Leaves thin, large, 

 ones heart-shaped, pointed; middle cites ovate; upper becoming lanceolate. 



Fionas in a broad flat-topped corymb, large, very open, -with long, narrow, whiu 

 rays. 



2. A. macrophyllus, L. Large-leaved Aster. 



Stem stout, branched, diffuse; leaves rough, thickish, serrate; louxr and radical 

 ones on long petioles, cordate ; upper on winged petioles or sessile; heads in large 

 corymbs; rays 12 to 25. 



Woods : common. Aug., Sept. Slon 2 to 3 feet high, rigid, the branches rough, 

 downy above. /. ■ r ' ves -4 to 10 inches long, and 3 to (5 incbes wide en some- 

 what winged petioles. Heads in a spreading' terminal corymb. Scales of tiu 

 involucre oblong-lanceolate, obtuse. Bays white or pale-blue. 



8. C-i.iUASTP.rM. T.&.G. Scales imbricated with spreading green tips ; rays 12 to 30, 

 : achenia narr to, smo tfush ; p ipj us rigid, of unequal Qa 



large and showy ; stem-leaves cdl sessile; lower ones not cordate. 



3. A. Radula, Ait. Rough-leaved Aster. 



Stem erect, simple btlow, angular, smooth; leaves cblcng-lanceolate, pointed, 

 simple, sharply serrate, rough on both sides and rugose-veined: involucre bell- 

 shaped, with oblcng appressed scales, and small spreading green tips; achenia 

 smooth, linear-oblong. 



Bogs and low grounds ; rare. Aug., Sept. Stem 1 to 3 feet high, very leafy, with 

 a few spreading undivided branches at tbe summit, purplish, each bearing a single 

 y more. Leaves 2 to 3 incbes long, nearly equal throughout. 

 Involucre nearly smooth, except the ciliate margins. Lags light violet-purple. 



4. A. spectabilis, Ait, Showy Aster. 



Stem erect, minutely rough aud glandular-pubescent at the summit; leaves 

 oblong-lanceolate, very rough, upper sessile and entire, lower ones serrate in the 

 corymbose ; heeds hemispherical, with numerous linear-oblong 

 ubtuse scales, and conspicuous spatul ate downy tips; achenia slightly pubescent. 



Sandy soil. Aug. — Nor. Stem 2 to -i feet high, branched above into a nearly 

 fhnple corymb of 10 to 15 heads. Hags about 2U in a head, narrowly-lanceolate, 

 nearly 1 inch loafi very deep- violet blue, probably the handfouitst of thajgnna. . 



