COMPOSITE FAMILY. 233 



S. latifdlia, Linn. Stem angled and zigzag ; leaves broadly ovate, 

 strongly serrate, pointed both ends ; rays 3-4. N. and S. 



S. Curtfsii, Torr. & Gray. Stem angled ; leaves oblong "or long- 

 lanceolate, with narrow, entire base, toothed above ; clusters loose ; rays 

 4-7. Va., S. 



S. bicolor, Linn. Gray-hairy, strict ; leaves oblong or elliptic, some- 

 what serrate ; upper clusters spicate or nearly panicled ; involucral scales 

 very obtuse ; rays 5-14, cream-color. N. and S. 



S. montfcola, Torr. & Gray. Nearly glabrous ; leaves oblong-ovate 

 or narrower, the lower sparingly serrate ; scales acutish j rays yellow, 

 5-6. Md., S. 



*+ *-* Heads in a compound terminal corymb, not at all axillary or 



racemose. 



= Leaves folded and recurved. 



S. Ridd^llii, Frank. Smooth, 2-4, very leafy ; leaves long linear- 

 lanceolate, those on the stem mostly clasping ; heads 20-30-flowered, very 

 numerous. Grassy lands, Ohio, W. and S. 



= = Leaves flat. 



S. rigida, Linn. Rough, somewhat hoary, 2-5, very leafy ; leaves 

 oval or oblong, thick ; heads large, 30- or more-flowered ; rays 7-10. N. 

 Eng., S. and W. 



S. Ohio^nsis, Riddell. Very smooth, 2-3, leafy ; stem leaves 

 oblong-lanceolate, the radical ones elongated and with margined petioles ; 

 bead 16-20-flowered ; rays 6-7. W. N. Y., W. 



M. -w- -n- Heads in a terminal panicle, or sometimes in a thyrse, small or 



middle-sized. 



= Leaves painly 3-ribbed; heads in l-sided sprays. 



II Both stem and leaves smooth and glabrous (or stem roughish only 



above). 



o Leaves firm, thickishf outer involucral scales short and ovate, the inner 

 oblong -linear, all obtuse. 



S. Missouriensis, Nutt. Smooth, l-3 ; leaves linear-lanceolate or 

 the lower broader ; clusters of heads racemose in a short and broad, 

 rather open panicle ; akenes nearly glabrous. Wis., S. and W. 



S. Shdrtii, Torr. & Gray. Roughish above ; leaves oblong-lance- 

 olate ; panicle short and crowded ; akenes pubescent. S. O. and S. W. 



o o Leaves' thinnish; scales linear, obtuse. 



S. Leavenw6rthii, Torr. & Gray. Strict and rigid, 2-4, scabrous 

 or puberulent above ; leaves mostly linear, sharply and finely serrate ; 

 panicle long and open ; rays 10-12, small. S. C., S. 



S. serdtina, Ait. Stout, 2-7, smooth and sometimes glaucous ; 

 leaves lanceolate and taper-pointed, serrate and ciliate, smooth; rays 

 7-14, rather long. N. and S. 



Var. gigant&a, Gray. Leaves pubescent, the lateral ribs more promi- 

 nent. Same range. 



[| || Stem and generally the leaves prominently pubescent or scabrous (S. 

 serotina, var. gigantea, above, may be sought here). 



o Plant green. 



8. Canad^nsis, Linn. Rough-hairy, stout, 3-6 ; leaves lanceolate 

 and pointed, serrate or sometimes almost entire, pubescent beneath and 



