224 



THE FLORA. 



g Ach. wit)i alongbeak, pap. silk-wliite. Heads erect, c. Wild Lettuce. "Lkcrv^cx. 

 g Acheniu not bciiked, pnppns dull-white. Hds. nod. c. Drop-flower. Nab'altjs. 10 

 g Achenia not beaked, pap. dull-white. PIds. erect, purple. S. r. Ltgodes'mia. 



521 523 519 520 



Achenia of Asterwovts, showing the varying pappus. Fig. 518. Acjenium of Eclipta, w 

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

 Fig. 521. Ageratum,— 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, witli close-pressed scales. Receptacle alveo- 

 late, narrow. Pappus simple, of equal, hair-like, rougii 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.) 



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



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



^ 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 



b Herbs (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 



b Heads in terminal compound corymbs. . . .n 



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



c Eacemes spreading or recurved, the flowers all on one side f 



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



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



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



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

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



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



f Leaves not veiny, thick, subcutive 27-29 



f Leaves evidently feather-veined, mostly serrate k 



