174 AMERICAN MIDLAND NATURALIST 
b. Stems simple. 
ce. Involucres large, 1.5—3 em. wide, ~sub- 
sessile or on short or rather long, ascend- 
ing pedicels, 
d. Heads subsessile in a dense spike, 
with more scarious, shorter bracts, 
achenes 6 mm) long... 8.0.0.4 2 .var. praecellens 
d. Heads with foliaceous, longer bracts, 
on shorter or longer pedicels, in an 
ample raceme, achenes 4 mm, 
LON SF KS Suey Chueh 11. var, Nreuwlanditi 
e. Stem short, raceme short, few- 
NERUCE: St WSS oS 12. forma borealis 
e. Bracts blackish purple... ......13. forma versicolor 
e. The whole plant very slender and 
protracted). owes > Gees 14. forma gracilima 
ce. Involucres 1.5 cm. wide, nodding. 
d. . Pedicels o:5-1 om. Jong. 0.05.05, ; 15. var. saluians 
dG: PedicelS:. r=a;5 ‘em. Jong." Shs. se. 3. var. nictiians 
ce. Involucres 1-1.5 cm. wide, on erect, 
short pedicels, or subsessile. 
d. Leaves of the upper series narrowed 
into petioles. 
e. Inflorescence a long, spike - like 
YaCOME Fie kN eee Ran Oe 16. var. pettolata 
e. Inflorescence short, subcorym 
DOSE. Sites a eee RE 17. var. subcymosa 
d. Leaves of the upper series not nar- 
rowed into petioles. 
e. Inflorescence a long, spike-like ra- 
ceme with its heads on some part 
of the rachis subcorymbose...... 
iS. var. corymbudosa Sheldon 
Inflorescence a long, spike-like ra- 
ceme without any subcorymbose 
oO 
interruption. 
f. Both series with short, oblong- 
lanceolate: leaves.:. 3... -<ga Sia. 1g. Var, virguana 
f. Leaves of the lower series elon- 
gated, lanceolate, racemes very 
