464  CocKERELL: NortTH AMERICAN SPECIES OF HYMENOXYS 
A. Plants less than 20 cm. high; perennials with large roots, and many stems; 
inflorescence usually flat-topped, not spreading ; pappus-scales long-acu- 
minate or arista a 
1. Pappus t half length of disc-corolla; heads large. (Saskatchewan. ) 
H. Richardsoni. 
appus-scales more than half length of disc-corolla. 2. 
2. Plant normally much over 10 cm, high, with large heads. 
Plant normally over 10cm. high, with medium-sized heads; pappus- ps 
ormally about three quarters length of disc-corolla. (Helena, Mon- 
tana, through middle Wyoming to the extreme north of Colorado. ) 
H. Richardsoni liguiaflora. 
Plant normally under 10 cm. high, heads medium-size 4. 
3. Heads up to 2 cm. across, exclusive of rays. (Wyoming. ) 
H. Richardsoni macrantha Nelsont, 
Heads 12 to 16 mm. across, exclusive of rays; rays very conspicuous; 
appus-scales normally about two thirds length of disc-corolla, (Sow 
central Wyoming and the mountains of the northern half of Colorado. ) 
H. Richardsoni macrantha. 
Heads about 10 mm. across, exclusive of rays; foliage and bracts paler 
than in the last, and the rays shorter. (Utah. ) 
H. Richardsoni macrantha Utahensts. 
4. Flowers rather inconspicuous ; foliage pale and wiry. (Western Wyoming 
to the mountains of Southern Utah. ) H. Richardsoni pumila. 
Flowers more SE Re with large rays; inner bracts gradually taper yo 
to apex. (Assiniboia. ) H. Richardsoni pumila Macou 
B. Plants normally 25 cm. high or more, with straight erect stems, and very 
numerous aii dick heads (6 to § mm. diam. excl. rays) ; perennials 
with large roots 
I. Stems not very numerous, scarcely at all woolly at base ; heads rather flat ; 
outer bracts conspicuously tipped with dark green; pappus- -scales short- 
pointed ; leaf-segments up to 2.5 mm. broad. (Mancos, Colo.) 
H., Earle. 
Stems usually very numerous, often very woolly at base; bh jak more 
ot convex ; leaf-segments very narrow, normally not over I mm. broad. 
2 
2. Well-developed plants 30 cm. highs _—— eet very woolly at base; 
pappus and achene-h lly more or , pa us-scales 
long-pointed. (Southern central Colorado and iether New Mexico.) 
H. floribunda. 
Well-developed plants about 26 cm. high; stems very w oolly at base ; 
pappus and achene-hairs normally shining on. -white. (Buena Vista 
and adjacent parts of Colorado, at 2,280~-3,000 m. ) ne 
fi. floribunda utilts. 
Differs from the last two by the short- -pointed Ps SAR. ; stems not very 
woolly at base ; heads rather a (San Francisco Mountain region of 
Arizona. ) H. floribunda arizonica. 
Plant more slender, pale; achene-hairs pale ferruginous ; pappus-scales 
fairly long-pointed, with ferruginous base. (Arizona and New exico- ) 
H. floribunda inne 
ae 
DR ine 
