416 Compositaceae 
GROUP 2 
A.  Herbage densely white-woolly or floccose at least when young, this usually persistent. 
B. Leaves lyrate-pinnatifid. E, 
S. uintahensis Nels. 
BB. Leaves not lyrate pinnatifid. 
C. Leaves on the same plant 1—2 cm. wide. 
Leaves entire to distinctly dentate or even lobed on the same plant; upper 
leaf-surface often glabrate. E. (S. howellii; S. canus purshianus; S. pursh- 
ianus. ) S. canus Hook. (Silvery Rag-wort) 
DD. Leaves entire or sparingly dentate; upper leaf-surface usually permanently 
woolly. W.E. (S. fastigiatus macoumii. ) 
S. fastigiatus Nutt. 
CC. Leaves on the same plant 15 cm. wide. 
E. Involucre-bracts conspicuously black-tipped. C. E. 
S. elmeri Pip. 
EE. Involucre-bracts not conspicuously black-tipped. W. (S. altus.) 
S. lugens Rich. 
AA. Herbage not densely white-woolly, pubescence mostly at stem-base and leaf-axils. 
F. Heads rayless. 
G. Annual. W. E. A. vulgaris L. (Common Groundsel) 
GG. Perennial. 
H. Stem-leaves deeply parted. W. E. 
S. pauciflorus Pursh 
HH. Stem-leaves entire to dentate, or rarely some of them parted. C. E, 
(S. elongatus.) S. cymbalarioides Nutt. 
FF. Heads radiate. : 
I. Heads’ !—2 on a stem. 
J. Stem-leaves bract-like. C. E. (S. valerianella.) 
S. subnudus DC. 
JJ. Stem-leaves wide and somewhat clasping, closely pectinate. C. 
S. ovinus Gr. 
II. Heads few to many on a stem, rarely only 1—2 on dwarfed forms. 
K. Akenes hispidulous on the angles. W. E. 
S. balsamitae Muhl. (Pop-soda Plant) 
KK.  Akenes glabrous. 
L. Leaves entire to shallowly pinnatifid, but not more deeply dissected. 
M. Basal leaves gradually narrowed to the petiole. 
N. Stems 1—3 dm. high; upper stem-leaves auricled. E. 
S. rydbergii Nels. 
NN. Stems 3—9 dm. high; upper stem-leaves not auricled. W. 
S. oreganus How. 
MM. Basal leaves abruptly contracted to the petiole. 
O. Basal leaves obovate or oblanceolate, dentate only toward the apex. 
(See HH.) 
OO. Basal leaves crenate-dentate from base to apex or nearly entire. C. 
S. fraternus Pip. : 
LL. Some of the leaves pinnately divided or more deeply lobed. 
P. Pubescence of crisp hairs. 
Q. Plant leafy to the inflorescence; leaves thin. eWeek 
S. harfordii Greenm. 
QQ. Plant not leafy above; leaves thick. W. 
S. flettii Weig. 

