Oeder 70.— ASTEEWORTS. 



229 



8 O. latifo'lia. Stem 4^6f. high. Eays entire. Leaves ovate, serrate. S. 



9 O. aurioiila'ta. Stem l-3f. high. Eays 2-5-toothed. Lvs. often eared at base. S. 



10 O. lanceola'ta. Stem 2-Sf. high. Eays 4^5-toothed. Lvs. lanceolate, entire. S. 



11 C. senifo'lia. Leaf divisions all entire, appearing in 6-leaved whorls. S. , 



12 O. verticilla'ta. Leaf divisions all again divided into narrow-linear lobes. W. 

 IS C, palma'ta. Lvs. deeply 3-cleft, wedge-shaped, lobes linear, not whorled. W. 



14 0. delphinifo'lia. Leaves sessile, 3-parted, the divisions often lobed. S. 



15 C. glacUa'ta. Sword-Vo. G. Leaves petioled, lance- 



olate, sometimes divided. Stem round. S. 



16 O. angnstifo'Ua. Narrow-lm. 0. Leaves petioled, 



narrow-spatulate, entire. Stem square. S. 



17 O. CEm'leri. (Emler'i 0. Leaves petioled, lanoe- 



ovate, entire. Stem round below. S. 



18 O. Dnunmon'dii. Srummond? s G. Lvs. pin- 



nately 8-6-foliate, divisions oblong-oval, 

 entire, t 



19 O. tincto'ria. Dyer's G. Leaves pinnately 



much divided, divisions linear, entire, t 



20 O. ro'sea. Hose G, Stem leafy, leaves narrow- 



linear, entire. Eays rose-white. E. 



21 O. nuda'ta. Leafless C. Stem few-leaved, leaves 



awl-shaped, entire. Eays rose-red. S. 



5. ASTER. Starwort. 



Heads many-flowered. Scales of the invo- 

 lucre generally imbricated in two or more 

 rows, and with green tips. Disk florets tubu- 

 lar, perfect, rays fertile, in one row, oblong, 

 revolute when old. Receptacle flat, marked ^- ^^ ■*■"'"■• P**^""- 



with pits. Pappus simple, hair-like, rough. Achenium usually flattened. 

 — A large genus of U herbs, very abundant in the United States, flower- 

 ing in late summer and autumn. Leaves alternate ; disk florets yellow, 

 changing to purple ; rays blue, purple, or white, never yellow. — The spe- 

 cies are very variable, and many of them are hard to distinguish. 



* Eadical and lower leaves cordate and potiolate a 



* Radical leaves never cordate o 



a Heads in loose corymbs. Eays white or whitish. . . .1, 2 

 a Heads in racemes or panicles, blue or bluish. . . .b ~ 



b Leaves evidently serrate ; rays light blue, about 12, spreading i' . . .3, 4 



b Leaves entire or nearly so ; rays bright blue, spreading near 1' 5-7 



c Involucre scales tipped with green, or the outer ones wholly green d 



o Involucre scales with scarious margins or wholly scarious f 



