240 



THE FLORA. 



W. 



8 C. latifo'lia. Stem 4-Gf. high. Eays entire. Leaves ovate, serrate. S. 



9 0. auricula'ta. Stem l-3f. high, Eays 2-5-toothed. Lvs. often eared at base. 



10 0. lanceola'ta. Stem 2-3f. high. Eays 4-5-toothed. Lvs. lanceolate, entire. 



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



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



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

 li C. delphinifo'lia. Leaves sessile, 3-parted, the divisions often lobed. S. 



15 C. gladia^ta. Stco?'d-lv. G. Leaves petioled, lance- 



olate, sometimes divided. Stem round. S. 



16 C. angustifo'lia. Narrow-li). G. Leaves petioled, 



narrow-spatnlate, entire. Stem square. S. 



17 C, CEm'leri. (E)iiler''s G. Leaves petioled, lance- 



ovate, entire. Stem round below. S. 



18 C. Drummon'dii. DrummonxV s G. Lvs. pin- 



nately 3-5-foliatc, divisions oblong-oval, 

 entire, t 



19 O. tincto'ria. Dijet^s G. Leaves pinnately 



much dividec^^ divisions linear, entire, t 



20 0. ro'sea. Rose G. Stem leafy, leaves narrow- 



linear, entire. Eays rose-white. E. 



21 0. nuda'ta. Leafiess G. 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 ^'^- ^^^^ ^'^'' ^*''^'- 



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

 — A large genus of if 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 petiolate a 



* Eadical leaves never cordate c 



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



a Heads in racemes or panicles, blue or bluish b 



b liCaves evidently serrate; rays light blue, about 12, spreading k' . . .3, 4 

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



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



c Involucre scales with scarious margins or wholly scarious. . . .f 



