200 COMPOSIT/E. (COMPOSITE family.) 



very ; scales of the involucre leafy and spreading; achenia smooth. — A Western 

 species, a form of which, with narrower and less silvery leaves and scales, grows 

 on the mountains of North Carolina. — Stem 10'-20' high. Leaves }/ -\' 

 long. Heads showy. 



11. A. COncolor, L. Stem mostly simple, slender, hearing towards the 

 summit, the middle-sized heads in a long often compound raceme ; leaves lance- 

 olate, silky when young; the lowest ones oblong; scales of the obovoid involu- 

 cre lanceolate, apprcsscd, the subulate tips spreading; achenia silky. — Drv 

 sandy soil, Florida and northward. — Root sometimes tuberous. Stem l°-3° 

 high. Leaves erect J'- 1' long. 



* * Txavcs rough, all sessile or clasping and entire: heads chiefly solitary, terminat- 

 ing the branchlets: scales of the obovoid or bell-shaped involucre imbricated in several 

 rows, coriaceous, with herbaceous si ightly spreading tips: rags purplish-blue: achenia 

 hairy. 



-i- Leaves very small, sessile: heads small: scedes of the involucre spatulate. 



12. A. squarrOSUS, Walt. Stem slender, diffuse ; leaves oblong or tri- 

 angular-ovate, rcflcxed, very rough, sessile; the lowest spatulate. — Dry soil, 

 Florida to North Carolina. — Stem l°-2° high. Lowest leaves }/ long, the 

 others 2'' -3" long. 



13. A. adnatus, Nutt. Stem with the slender branches erect; leaves ob- 

 long, very rough, the midrib partly adnate to the stem, free at the apex; the 

 lowest wedge-obovatc, free. — Sandy barrens, Florida and Alabama. — Stem 

 l°-2° high. Heads smaller than in the preceding. 



4- -•- Leaves eill clasping and auricled at the base : hcaels large : scales of thj invo- 

 lucre linear. 



14. A. patens, Ait. Stem pubescent, loosely panicled above; leaves 

 ovate-oblong, with very rough and wavy margins ; those on the slender and 

 spreading branchlets very small. — Var. piilogifolius. Leaves larger, thinner, 

 and less roughened, contracted below the middle; heads often racemose on the 

 short lateral branches. — Dry soil, chiefly in the upper districts. — Stem l°-3° 

 high. Leaves l'-2' (in the var. 3' -6') long. Heads showy. 



* * * Leaves [and stems) smooth: the lowest tapering into a petiole, the others 



sessile or clasping: hotels middle-sized, showy: scales of the obovoiel involucre 

 whitish, the short green tips scarcely spreading : rays bright blue : achenia mostly 

 smooth. 



15. A. lsevis, L. Very smooth and often glaucous ; stem rigid, panicled 

 above, bearing the showy heads on short rigid branchlets ; leaves oblong or lan- 

 ceolate, coriaceous, mostly entire and rough on the margins; the upper ones 

 Bessile or clasping; Bcales of the involucre rigid, apprcsscd, with abruptly pointed 

 herbaceous tips. — Open woods in the upper districts. — Stem 2° - 3° high. 



10. A. gracilentus, Torr. & Gray. Very smooth; stem slender, loosely 



panicl.d above, bearing the heads at the end of slender leafy branchlets; leaves 

 linear, elongated ; the lower ones coarsely toothed above the middle, the upper 

 slightly clasping and entire ; scales of the involucre much shorter than the disk, 





