ORDER 70. ASTERWORTS. 



235 



g Ach. with a long beak, pap. silk-white. Heads erect, c. WM Lettuce. LACTD'CA 

 ? Achenia not beaked, pappus dull-white. Hds. nod. c. Drop-flower: NAB'ALTJS 

 g Achenia not beaked, pap. dull-white. Hds. erect, purple. S. r. LTGODES'"MIA 



521 523 



Achenia of Asterworts, showing the varying pappus. Fig. 518. Achenium of Eclipta, no 

 pappus. Fig. 519 Horseweed (Amlrosia trifida). Fig. 520. Sunflower; pappus 2 teeth 

 Fig. 521. Ageratuui, 5 scales. Fig. 522. Blue Lettuce, many hair-like bristles. Fig. 523. Wild 

 Lettuce, pappus raised on a beak. 



1. SOLID A'GO. Goldenrod. 



Heads few-flowered, the rays 1-15, pistillate, disk florets perfect. In- 

 volucre oblong, imbricate, with close-pressed scales. Receptacle alveo- 

 late, narrow. Pappus simple, of equal, hair-like, rough bristles. Herbs, 

 very abundant in the United States. Stem erect, branching near the top. 

 Leaves alternate. Heads small, florets all yellow (in S. bicolor, whitish), 

 opening from August to October. (See Figs. 501-503.) 

 1 Shrub woody, l-3f. high. Heads with 1-3 rays. S . . . *1 



If Herbs. Heads without rays (discoid). S 2, 3 



H Herbs. Heads with rays (1-15, generally small) a 



a Scales of the involucre with recurved, leafy, green tips 4, 5 



a Scales of the involucre erect, tips scarcely at all green . . . ,b 

 fa Heads (white or yellow) in axillary, close clusters or short racemes .... 6- 9 



b Heads in terminal racemes forming a close or a spreading panicle c 



6 Heads in terminal compound corymbs n \ 



c Racemes erect, not one-sided. Leaves feather- veined d 



c Racemes spreading or recurved, the flowers all on one side i 



d Alpine species (growing only on mountains). Heads qujte large 10-12 



d Not alpine growing in plains or low grounds. Heads not large . . . .o 



e Plants very smooth, at least the stem and leaves. Rays 4-7 13-15 



e Plants downy or hoary with very close soft hairs. Rays 9-12. . . 16,- 17 



f Leaves 3 or 1-veined. Very smooth salt-marsh herbs 18, 19 



I Leaves evidently 3-veined. Herbs inland, &c. . , .g 



f Leaves not veiny, thick, subcutive.. . .27-29 



( Iieaves evidently feather-veined, mostly serrate ..k 



