lb Involucres glovose, their bracts overlavving but not 
/O coalesced, each hooked at the apex 4&7, Arctiun 
involucres not burr-like, their bracts spine-tipvoed in virsium 
@ end Ventaurea, othervise herbaceous or vevery 7777 
T+ 7 7 a 7 . 4-6 is a * “4 al + 5 
6 Involucral br aces densely overlanping in several series, at 
soleast the outer ones tivped vith spines 
@ Leeves svinose on the marpins 44, Cirsium 
@ Leaves PAEIEO s linear-oblong 49 Centaurea 
(> Neither involucral bracts nor leaves spinose —— 
8 Marginal flowers much larger than the central 
jzones, funnel-shaped, showy 4¥ Centaurea 
® Warginal flowers not perceptibly larger than 
the central ones, tubular, rarely more 
rs than 5 mm. wide in the throat 
/oO Flowers few, mostly hidden, the marginal ones 
enclosed within the incurled involucral 
/ practs 
iz, involucral bracts boat-shaped, enclosing 
the pistillate marginal flowers and 
IU schones, l-several perfect flowers in 
the center; bracts glandular 30, La@ia 
iz, Involucral bracts strongly nooded, with a 
tiny appendage, becomins inflated 
obovate sacs opening on the inside be- 
TO oon che wiatie coclce ass a 
flowers and achenes; bracts woolly; 
diminutive annuals J). Psilocarchus 
yo Flowers nwaerous, apparent, none enclosed 
M4 by incurled bracts 
barbed awns at the apex of the strongly 
}(, ( flattened achene, these therefore 
Clinging tenaciously to clothing Bidens 
IZ Fappus consisting or two rigid retrorsely ery 
nN 
17, Fappus none or consisting of numerous 
f, soft capillary bristles 
/4 3a.cappus consisting of conspicuous soft 
¢ hairlike bristles equal to tne 
/ involucres or 
be 
oO 
5 
G3 
Ge 
K 
> 
ji, Leaves 10-20 cm. broad, deeply 
Zpcoraate at the base 42, -etasites 
fi,Leaves 1-S cm. broaa or less, not 
a 
P| ake F ao a ee = poe © - 
,@ cordate or shallowly so, most 
Pee | narrowea AV tae base 
\ 
