FIFTEENTH REPORT. 
-0G 
ee. Stem usually diffuse-bran died ; heads rather more numer- 
ous, in larger clusters, (rich woods) 8. caesia 
dd. Lower leaves broadly oval, obtuse, thickish, crenate; achenes 
glabrous, (dry soil) *Sf. erect a. 
bb. Stem and both sides of the leaves more or less pubescent, or 
sometimes glabrous. 
c. Rays white, (dry soil) 8. bicolor 
cc. Rays yellow, (dry soil) 8. hispida 
aa. Heads not in clusters or short racemes in the axils of ordinary 
foliage leaves; not thyrsoid. 
b. Heads crowded at or near the ends of the branches at about 
the same distance from the base of the panicle, forming a 
rounded or flat-topped inflorescence, 
c. Lower leaves ovate, oblong or oval, pinnately veined. 
d. Stem and both sides of the leaves rougli-pubescent. (dry, 
sandy soil) 8. rigida 
dd. Stem and both sides of the leaves glabrous, (bogs and 
swamps) 8. ohioensis 
cc. Lower leaves linear-lanceolate, 3-5-ribbed. 
d. Heads few, in a small, corymbose cyme; leaves few, scat- 
tered. (lake shores) $. Houghtonii 
dd. Heads many, in a large, dense, corymbose cyme; stem very 
leafv. 
e. Leaves glabrous both sides. 
f. Leaves folded, 8-20 mm. wide; basal leaves long-petioled. 
(swamps) 8. Rid dell ii 
ff. Leaves flat, 1-8 mm. wide; basal leaves not long-petioled. 
g. Leaves 4-8 mm. wide, distinctly 3-5-ribbed. (moist 
soil) 8. graminifolia 
gg. Leaves 1-4 mm. wide, usually with prominent midrib 
only, (dry, sandy soil) 8. tcnuifolia 
ee. Leaves hairy both sides, (damp soil) 
*8. graminifolia , r. Xnttallii 
bb. Heads more or less uniformly distributed along the length of the 
branches, forming a cylindrical or pyramidal inflorescence, 
never flat-topped. 
c. Pauline leaves 2-5 Inflow the inflorescence, (highest elevat'ons 
of the Upper Peninsula) 8. P utleri 
cc. Pauline leaves 5-many below the inflorescence. 
d. Basal leaves much exceeding the greatly reduced upper ones, 
e. Racemes or branches of the panicle either short and ar- 
ranged along a more or less elongated central axis, or 
elongated and ascending, scarcely recurved, forming a 
narrow, more or less elongated panicle (cylindrical or 
thyrsoid type), (compare with a). 
f. Leaves mostly entire, the uppermost usually without 
axillary fascicles, (dry, open woods) 8. speciosa 
ff. Leaves mostly serrate, at least the basal ones, the upper- 
most usually with axillary fascicles, 
g. Heads on pedicels 5-15 mm. long; achenes pubescent; 
stems usually clustered. 
