Order 70.— ASTERWORTS. 241 



d Stem leaves c.asping, with a cordate or anricled base e 



d Stem leaves sessile, rarely clasping, never cordate or anricled.... 19 



e Involucre scales close, in several rows, outer ones gradually sliorter. . , .8, 9 



e Involucre scales loOf=e, nearly equal, outer ones often wholly green 10-12 



f Leaves lanceolate and linear-lanceolate, more or less rough 13-15 



f Leaves linear, flesliy, very smooth, entire. Salt-marsh herbs 16-18 



1 A. corymbo'sus. Corymbed S. Slender, with thin, serrate leaves. 



2 A. macrophyl'Ius. Big-lvd. S. Stout, with large, thick, ser., rough Ivs. 13-rayed. 

 8 A. cordifo'lius. Heart-leaved S. Involucre scales close, obtuse. Lvs. sharp-serrate. 

 4 A. sagittifo'lius. Arrow-leaved S. Scales awl-shaped, long, loose. Lvs. blunt-serrate. 



5 A. azu'reus. Azure S. Stem leaves sessile, rough, lanceolate, and linear. 



6 A. undula'tus. Stem lvs. on winged stalks, with rounded clasping bases, wavy. 



7 A. Shor'tii. SliorVs S. Stem leaves on naked stalks, all cordate, pointed, entire. 



8 A. patens. Patent S. Plant rough-downy. Leaves entire. Scales pointed. 



9 A. laevis. Polished S. Plant smooth and glaucous. Scales broad, acute. 



10 A. prenanthoi'des. Lvs. sharply cut-serrate, with a long, slender, entire base. 



11 A. punic'eus. Eed-st. S. Lvs. sparingly serrate, lance. Stem hairy, often red. 



12 A. Novae-Angliae. New-England S. Leaves entire, rough, numerous. Raya 



nearly 100, %' long. Stems 4-6f. high. A fine species, often cultivated. 



13 A. acumina'tus. Bell S. Leaves coarsely-toothed, broad-lanceolate, long-pointed, 



often clustered. Kays white. In dark woods. N. 



14 A. nemora'iis. Wood S. Leaves narrow-lanceolate, nearly entire, acute, with 



edges revolute. Heads 1-3. In damp woods. N. M. 



15 A. ptannicoi''des. Sneezeioort S. Leaves entire, stiff, acute. Heads corymbed. 



16 A. flexuo'sus. Zigzag S. Headsjarge, with showy rays. Stem fiexuous. 



17 A. liniro''Iius. Flax S. Heads numerous, with very sliortrays in 2 rows. 



18 A. subala'tus. Heads with showy blue rays. Scales in 2 or 3 rows. S. 

 19 Ma :y species, very variable, here omitted. (See p. 420, Class Book.) 



6. ERIG'EROK Fleabane. Whiteweed. 



Heads many-flowered, mostly hemispherical, rays very numerous 

 (20-200), narrow, linear, pistillate ; disk flowers perfect. Receptacle flat, 

 naked (no chafi'or pits). Scales of the involucre nearly equal and in one 

 row. Pappus generally simple. — Herbs with alternate leaves. Rays 

 white, blue, or reddish. Flowering from May to September. 



^ Rays showy, longer than the involucre. Heads large {\-V broad) a 



• Rays obscure, shorter than the involucre, whitish. Heads very small 1, 2 



a Rays p.irple, very numerous. Heads loosely corymbed 3-5 



a Rays Mhite or whitish. Heads loosely panicled 6-8 



1 E. Canaden'se. Canada F. Erect, hairy. Leaves lanceolate. Heads panicled. 

 8 E. divarica'tum. Prostrate F. Low, diffuse. Lvs. linear. Heads corymbed. W, 



11 



