COMPOSITE. (COMPOSITE FAMILY.) 207 



bristles in two rows, the outer row much shorter. Perennial erect herbs. 

 Leaves alternate. Heads single or corymbose. Rays white or purple. 



* Rays purple. 



1. D. linariifolius, Hook. Stem rigid, simple, closely pubescent; leaves 

 numerous, linear, spreading, the margins very rough ; heads solitary or some- 

 what racemose ; scales of the involucre imbricated in several rows, linear, ap- 

 pressed; achenia silky. Dry open woods, West Florida to Mississippi, and 

 northward. September. Stem 1 high. Leaves 1 ' long. 



* * Rays white. 



2. D. COrnifolius, Darl. Stem pubescent ; leaves elliptical, tapering at 

 each end, t hairy on the margins and veins beneath ; heads few, on slender 

 spreading peduncles ; achenia smooth. Upper districts of Carolina, and north- 

 ward. August. Stem 1 - 2 high. Leaves 2'- 4' long. 



3. D. amygdalinus, Torr. & Gray. Stem roughish and corymbose 

 above ; leaves oval or oblong, acute at each end, nearly smooth ; heads numer- 

 ous, corymbed ; scales of the involucre obtuse ; achenia hairy. Swamps, Flor- 

 ida, and northward. September. Stem 2 - 4 high ; the branches spreading. 

 Leaves l'-2' long. 



4. D. umbellatus, Torr. & Gray. Stem smooth, corymbose above ; 

 leaves lanceolate, acuminate ; scales of the involucre acutish ; achenia hairy. 

 Swamps in the upper districts. September. Stem 3 - 6 high. Branches 

 erect. Leaves 3' -5' long. 



5. D. obovatus, Torr. & Gray. Closely pubescent ; stem simple, scaly 

 at the base ; leaves oblong, sessile, strongly veined ; heads large, corymbed, on 

 long and naked (whitish) peduncles ; scales of the involucre acute ; achenia 

 hairy. (Aster obovatus and A. dichotomus, Ell.) Low pine barrens, Florida 

 to South Carolina. May - July. Stem 1 - 2 high. Leaves 1 ' - 2' long. 



19. BOLTONIA, L'Her. 



Heads many-flowered. Rays pistillate. Scales of the hemispherical involucre 

 imbricated in two rows, not longer than the disk. Receptacle hemispherical or 

 conical, obscurely alveolate. Achenia flattened, obovate, wing-margined. Pap- 

 pus composed of several short chaffy scales ; that of the disk-flowers mostly 

 with 2-4 longer awns. Perennial herbs, resembling Asters. 



1. B. diffusa, Ell. Stem with long and slender branches ; leaves linear, 

 entire ; heads small, terminal ; achenia narrowly margined, hairy ; pappus very 

 short, 2-awned. Damp soil, Florida to North Carolina, and westward. Sept. 

 and Oct. Stem 3 -4 high. Rays purplish. 



2. B. glastifolia, L'Her. Stem paniculate ; leaves rigid, lanceolate, 

 sparingly serrate ; the upper ones linear, entire ; heads rather large ; achenia 

 broadly margined ; pappus of few short bristles, and 2-4 long awns. River 

 swamps, Florida, and northward. July - Sept. Stem 3 - 5 high. Rays 

 white. 



