154 COMPOSITE, (composite family.) 



cence when developed of naked and secund commonly recurving raceme-like 

 clusters collected in a terminal panicle. 



5. S. Missouriensis, Nutt. Low or middle-sized: leaves thickish, with 

 scabrous margins, mostly taperiug to both ends, and the serratures ichen pres- 

 ent sharp and rigid; lower spatnlate-lanceolate, larger 4 to 6 inches long; 

 upper mostly linear and entire, acute ; sometimes all entire : racemiform clus- 

 ters approximated in a short and broad panicle, recurving in age : rays 6 to 

 13, small : bracts of the involucre mostlij ovate. — From the eastern slopes of the 

 mountains to the Mississippi Valley States. 



Var. montana, Gray. Dwarf, 6 to 15 inches high: leaves entire or with 

 few small serratures ; cauline obscurely triplinerved, an inch or two long : 

 panicle small and compact, at most 2 or 3 inches long ; its clusters short, 

 crowded, seldom recurved or much secund. — Proc. Am. Acad. xvii. 195. 

 From Idaho to the Dakotas and the Saskatchewan. 



Var. extraria, Gray. A foot or two high, robust : leaves broader, the 

 largest sometimes an inch wide, sparingly seriate or entire : heads rather 

 larger: rays more conspicuous. — Loc. cit. Dry ground, in the mountains, 

 Colorado to S. Arizona. 



6. S. serotina, Ait. Stem stouter and taller, 2 to 1 feet high, very smooth 

 up to or near the ample panicle, which is sometimes more or less hairy : leaves 

 thinner, lanceolate or broader, sharplij and sahentlij serrate: rays 7 to 14, mod- 

 erately large and conspicuous: bracts of the involucre broadlg linear. — From 

 Oregon to Texas and eastward. 



++ *+ Minutelg pubescent or gldbrate, not cinereous or scabrous: leaves thinnish, the 

 lateral ribs generally obscure : panicle mostly erect and thyrsiform ; heads little 

 if at all secund : rays 12 to 18, small. 



7. S. elongata, Xutt. One to three feet high : leaves lanceolate to oblong, 

 3 or 4 indies long, very sharply and mostly coarsely serrate : thyrsus ratlier 

 compact, 3 to 8 inches long, its branches occasionally spreading : bracts of the 

 involucre linear, acutish or obtuse. — From California to British Columbia" 

 and eastward to Montana. 



4H. ++ ++ Pubescent {at least the stem), either hlrsutely or canescently : branches oj 

 the panicle when well developed secund. 



= Leaves tapering gradually to an acute or acuminate point, generally thin or 

 thinnish: panicle open, of naked and secund mostly recurving racemiform clus- 

 ters : bracts of the involucre narroio and thin : rays small and short. 



8. S. Canadensis, L. Stem 2 to 6 feet high, from scabrou.s-puberulent 

 to hir.sute: leaves mostly lanceolate, puberulent, pubescent, or nearly glabrous, 

 sharply serrate or the upper entire, veiny, and with lateral ribs prolonged par- 

 allel to the midrib : heads small, ordinarily only 2 lines long : bracts of the 

 involucre small and pale, narrowly linear, acutish or obtuse: rays 9 to 16, 

 more numerous than the disk-flowers. — From Arizona to British Columbia 

 and eastw^ard across the continent. 



Var. procera, Torr. & Gray. Leaves less serrate or the upper entire, at 

 least the lower face and upper portion of the stem cinereous-pubescent with 

 very short and fine pubescence : inflorescence less open or the branches ascend- 

 ing in less developed or cultivated plants: heads sometimes larger. — From 

 Idaho to Texas and the Saskatchewan. 



