390 Compositaceae 
h. Annual; heads many; -pappus double, the outer whorl of short 
subulate bristles. E. 
E. divergens T. & G. (Spreading Flea-bane) 
hh. Perennial; heads | to few on each stem: pappus of a single whorl 
of bristles. W. E. glaucus Ker. 
SS. Blades of the basal leaves linear or lanceolate; leaves all entire. 
1. Stems unbranched, usually with only | head. 
j. Rays blue or purple, 30-40. W. E. pacificus How. 
jj. Rays white or ochroleucous. 
k. Leaves linear-lanceolate; rays 20—50, white. E. 
E. nevadensis Gray 
kk. Leaves narrowly linear. 
I. Plant I—2.5 dm. high, hirsute; rays 50—80, white. (See e.) 
I]. Plant 2.5—4.5 dm. high, ashy-pubescent to glabrate; rays 
40—60, white or ochroleucous. (See E32) 
il. Stems branched, usually with several to many heads. 
mp Rays.20— 30. 
n. Leaves 3-veined, linear-lanceolate. (See Z.) 
nn. Leaves |-veined, linear or filiform. W. E. (E. decumbens.) 
E. linearis Pip. 
mm. Rays 50—80. 
o. Rays 6—8 mm. long, white. (See e.) 
oo. Rays about 12 mm. long, white or purple or violet. E. (E. 
hispidissimus. ) E. concinnus T. & G. 
HH. Leaves dissected or deeply cleft. 
p. Leaves 2—3 times ternately-parted or -divided. F. 
E. compositus Pursh 
pp. Leaves once ternately- or quinately-cleft or parted. W.C.E. (E. tri- 
fidus. ) E. compositus trifidus Gray 
AA. Rays very short or none. 
q. Lower stem-leaves ternately-cleft or -parted. C. 
E. compositus discoideus Gray 
qq. Leaves entire or merely dentate. 
r. Stems unbranched, mostly with only | head, tufted, 5—15 cm. high. 
s. Herbage more or less ashy-puberulent. FE. E. bloomeri Gray 
ss. Herbage glabrous. U. E. nudatus Gray 
rr. Stems branched, mostly with few to many heads, not tufted. 
t. Heads cymose; rays none; involucre glabrous; perennial. C. F. (E. in- 
ornatus. ) E. eradiatus Pip. (Pine Flea-bane) 
tt. Heads paniculate; rays short; involucre glabrous; annual. W. E. (Leptilion 
canadense. ) E. canadensis L. (Horse-weed) 
ttt. Heads cymose; rays short; involucre hairy at base; biennial. 
u. Hirsute pubescent; basal leaves spatulate. C. E. 
E. acris L. (Bitter Flea-bane) 
uu. Sparsely pilose; basal leaves obovate to oblong. W. C. E. 
E. acris debilis Gray 
uuu. Glabrate or glabrous; basal leaves spatulate. C. 
E. acris droebachensis Blytt. 
SERICOCARPUS WHITE-TOPPED ASTER 
Herbs, perennial; ours 3—6 dm. high, leafy to the top, glabrous to slightly rigid- 
pubescent. Leaves alternate; in ours oblong-lanceolate, entire, 2.55 cm. long. Heads 
radiate, |2—15-flowered, 10-15 mm. long (ours), in cymose panicles; involucre ob- 
