912 LXXV. COMPOSIT. 
ppus capillary... Vernonia. 1 
Scales much imbricated. }Peeeme a . Liatris. 7 
; phi ros s _ ion . 50 
Scales in 2 series, . .. (erect, greenis S U ntiopus. 2 
Flowersall perfect. Scales in 1 row or series. . " “a lia. 51 
Receptacle ; Heads heterogamous Gnaphalium. 54 
Scales 4 not chafty. ?@ Heads diccious. . Antennaria. 55 
colored. ( Receptacle chaffy. . Filago. 56 
Fls. all ¢ nvol imbricated. | Pluchea. 23 
equal. @Invol. calyculate. . Erechtites. 57 
Plants Scales § Herbs. ( Ray flowers larger, sterile. . Centaurea. 62 
unarmed. (Fis. notall perfect. \green. @Shrubby. Heads diecious. . . Baccharis. 24 
Scales acute- $ Achenia smooth. . Cirsium. 69 
with spinose 4 cuspidate. . . ? Achenia rugase, ‘angled. - Onopordon. 67 
eaves..... Scales emarginate- -mucronate. . . Cynara. 68 
: : ; Heads homogamous. x ? . Lappa. 70 
§ 1. | Plants armed. | with spinose heads anly. ? Heads heterocephalous. . . Xanthium. 58 
; Receptacle flat. | 4 
§ homogamous. ? Receptacle conten Conoclinium. 6 
; Heads many, ? heterocephalus. 7 ye ee Ambrosia.  —S9_ 559 
§ erect. Head solitary, terminal. 2. fg Sclerolepis. 3 
stacn herbaceous, ?climbing andtwining. . . . +. . +. +. =. Mikania. 5 
§ 2. Stem shrubby. Heads monecious. Seas Meee yo et 60 
Heads corymbose. . Tanacetum. 53 
ken Heads racemose. . . Artemisia. 52 
dry, (spreading, petaloid, yellow. . Xeranthemwn. . 
green. 3 
S onoct, , close, Peliowsiah. Bigelovia. 22 
Corollas § Scales unarmed, (herbaceous, ¢ spreading and loose. . Carthamus, 64 
‘Leaves all equal. 2 Scales of the involucre doubly BDINGAS. Pie yore 6 oS 66 
‘alternate. ¢ Outer corollas enlarged and sterile. _. ee boa. 63 
jAwne of the achenia retrorsely hispid. = Ft fits naa be 46 
§ 8. (Leaves opposite. ? Awns of the é achenia upwardly hispid. Ri eopsis. 45 
§ Heads small. Solidago. 1s 
Involucre Pappus simple. ? Hds. ven Site. Inula. Ql 
imbricated. ? Pappusdouble. Hds. size. Chevagpas. 20 
flat or | Involuc. not $ Outer scales very short or 0. . Senecio. 49 
convex. \imbricated. Outer scales equal to the inner. Catenduta. 61 
Ray flowers pistillate. . . Heleniwm. 36 
Receptacle not chaffy, (conical or globose. . . ? Ray flowers neutral. tar Top 43 
. q Achenia quadrangular. . Rudbeckia. 30 
Pappus minute or 0. 2? Achenia compressed. achys. 32 
Rays 4 Pappus of 2caducous awns. Achenia wingless. Helianthus. 34 
sterile. ( Pappus of 2 persistent awns. Achenia winged. Acti 44 
§ 4. \ Receptacle chaffy. ( Rays fertile. Ach. obcompressed (parallel with the scales). Si/phiwm. 27 
Awns ofach. retrorsely hispid. Bidens. 46 
: piexeleare double. ? Awns ofach. erectly li . Coreopsis. 45 
Rayssterile. ? Involucre imbricate in 3 or more rows. . . Helianthus. 34 
: : Achenia obovoid, thick... ._ Polymmnia. 26 
disk sterile... . @ Achenia obcompressed, winged. Silphium. 27 
Receptacle , Receptacle nearly flat. . Verbesina, 47 
c ... Rays fertile, ( disk perfect... . @Receptacle conical.. . . Heliopsis. 29 
Scales 5, united in 1 row. . Tagetes, 35 
ata Sc. i Oe outerrow distinct. Dysodia. 48 
5 hme opposite, ? undivided. Scales distinct. . . . Arnica. _ 25 
§ 5. \Recept, not chaffy. ? Leaves radical, appearing after the solitary head. . pei. 8 
Rays white, shorter a scales. lipta. 19 
; Receptacle flat. ? Rays rose color. . . Coreopsis. 45 
F jrimnle. Receptacle conical, with large pale. > - Zinnia. 33 
Leaves opposite, ¢ pinnately divided. Inner invol. of 8 united scales. -  « Dahlia. 16 
3 ; Heads corymbose. . : - + + Nardosmia, 9 
§ 6. (Leaves all radical. . . Head solitary, heterozamous. - » Bellis. 15 
§ Achenia silky. Raysabout5. . Serico ll 
rows copious. ? Achenia smoothish. Rays 6—100. Aster. 10 
simple, 3 ce 2 short bristles and several minute ones. Boltonia. 17 
Heads middle size. . A . Diplopa 12 
eer \ Pappus double. Heads very large. . Callistep us. 14 
Pappus capillary. Invol. subsimple Rays 20—200. Erigeron. 13 
nesspatl : je olucre depressed, broad. _ . Leucanthemum, 40 
smoothish. ( Pappus none. . . 2? Involucre hemispherical. . . Chrysanthemum.42 
Rays pistillate. . Ant. is. 37 
ie 3 isk fls. yellow. ? Rays neutral. . Maruta. 38 
Lvs. finely divided. ? Disk fils. white. Rays pistes, .. Achillea. 39 
= 4. . Verbesina. 47 
; Rays very short, white, . . Parthenium. 28 
Receptacle chafly. | Leaves undivided. 2 Rays very large, purple. . . . Echinacea. 31 
in 2—3 rows. . Troximon. 81 
§ Scales of the invol. equal. ? in 1 row. P . Krigia. ome] 
— yellow. ? Outer scales shortest, pappus capillary. . . Taraxicum. 82 
Lys. radical. LS ea white ; pappus plumose. ‘odon. 74 
§ Pappus single, bristly. Hieraciwm. - 79 
ee s. unarmed. ? Pap. double, outersealy. Cynthia. 73 
_ (Fils. yellow. ? Lvs. spinose-dentate ; pappus very bab i Sonchus. 83 
Achenia< Flowers blue. Pappus small, scaly. 71 
not rost. ( Fls. whitish or cream color. Pap. copious, capillary. | Nabalus. 80 
_ (with a fili- pee hee with calyculate scales. . . Lactuca. 77 
Achenia< form beak. ? Involucre without calyculate scales. . Tragopogon. 75 
Lvs. cauline. | rostrate. ( with a short, thick beak; involucre imbricate. . — - Mulgedium. 78 
