COMPOSITE FAMILY. 233 



S. Iatif6lia, Linn. Stem angled and zigzag ; leaves broadly ovate, 

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



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

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



4-7 Va S 



■' ■ = = Akenes glabrous. 



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, 'I'orr. & Gray. Nearly glabrous ; leaves oblong-ovate 

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

 5-6. Md., S. 



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



racemose. 



= Leaves folded and recurved. 



S. Ridd^Ilii, 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 \V. 



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. 



++*+■«■ Heads in a terminal panicle, or sometimes in a thyrse, small or 



middle-sized. 



= Leaves painly ii-ribbed ; heads in I- sided sprays. 



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



above). 



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



oblong -linear, all obtuse. 



S. Missourienais, 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. Sh6rtii, Torr. & Gray. Roughish above ; leaves oblong-lance- 

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



o o Leaves thinnish ; scales linear, obtuse. 



S. Leavenw6rthii, Toit. & 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. ser6tina, 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. 



II II Stem and generally the leaves prominently pubescent or scabrous (^8. 

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



o Plant green. 



S. Canadensis, Linn. Kougli-hairy, stout, 3°-6° ; leaves lanceolate 

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



