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2. Vernonia. Heads several to many-flowered, separate: involucre of many 
scales: pappus double, the inner capillary, the outer of minute chaffy scales. 
Tribe II. EUPATORIACEAE. Heads discoid; the flowers all alike, perfect and tubu- 
lar, never yellow: style-branches elongated, more or less thickened upward and 
obtuse, minutely papillose, or puberulent, or glabrous: leaves either opposite or 
alternate. 
* Achenes 5-angled, destitute of intervening ribs. 
+ Pappus never wholly capillary. 
3. Stevia. Heads 3 to 5-flowered, cylindrical, with 5 or 6 mostly equal rather 
rigid involucral bracts: corolla narrow: pappus a crown of scales or awns, or com- 
posed of both. 
4. Trichocoronis. Heads many-flowered, with 12 to 18 lax herbaceous or sub- 
membranaceous equal and nerveless involucral bracts: corolla abruptly much dilated 
above the narrow tube: pappus minute or small, a crown of numerous bristles. 
+ + Pappus wholly of capillary and mostly uniserial bristles. 
++ Bristles of pappus merely scabrous, indefinitely numerous. 
5. Mikania. Flowers and involucral bracts only 4: stems twining. 
6. Bupatorium. Involucral bracts more than 4, and flowers few or many: stems 
not twining. 
++ ++ Bristles of pappus long-plumose, rather few, 
7. Carminatia. Involucre several-flowered, cylindraceous, of several lanceolate- 
linear 3 to 5-striate thin imbricated bracts, the outer shorter: achenes slender, nar- 
rowish at apex: pappus-bristles 10 to 18, plumose with long arachnoid hairs. 
** Achenes 10-ribbed or striate: involucral bracts regularly imbricated, the outer 
successively shorter. 
+ Involucral bracts not herbaceous, striate-nerved (conspicuously so when dry): 
pappus a single series of capillary bristles. 
&. Kuhnia. Pappus conspicuously plumose. involuecral bracts few. 
9. Brickellia. Pappus from barbellate to merely scabrous: involucral bracts in 
several series, 
+ + Involucral bracts somewhat herbaceous or partly colored, inconspicuously when 
at all striate (even when dry): |gaves punctate and entire. 
10. Carpochete. Heads 4 to 6-flowered, cylindrical, with acuminate rather few 
involucral bracts: achenes barely puberulent: pappus of long slender erose-dentic- 
ulate searious scales continued into a scabrous awn and with 1 to 5 small pointless 
scales: leaves opposite. 
11. Liatris. Heads 4 to many-flowered, with a spirally imbricate involucre: 
achenes pubescent: pappus about a single series of firm and mostly equal bristles, 
from plumose to barbellate: leaves alternate. 
Tribe III. AsTEROIDEs, Heads either discoid or radiate (the ray pistillate): 
anthers not cordate at base: style-branches of fertile flowers flattened and with a 
distinct hispid or papillose appendage: leaves mostly alternate, and receptacle mostly 
naked. 
* Ray flowers yellow, or sometimes none at all. 
+ Pappus of not numerous slender bristles, or wanting: heads radiate: involucre of 
firm bracts with greenish tips. 
12. Gymnosperma. Heads several-flowered, very small and numerous: ligules 
very small, not surpassing the disk-corollas: flowers all fertile: pappus wanting: 
neads in glomerate terminal cymes. 
13. Gutierrezia. Heads small and numerous: ray and disk flowers 3 or 4 each, all 
fertile: pappus of several short chaffy scales: suffrutescent, with very narrow leaves. 
