COMPOSITE. (composite FAMILY.) 221 



all on slender petioles, and obtuse or cordate at the base, commonly entire ; 

 those of the branches oblong, sessile ; scales of the bell-shaped involucre 

 linear, closely imbricated, rather obtuse, shorter than the disk. — Mountains 

 of Georgia, and westward. — Stem 2° -4° high. Rays violet-blue. 



21. A. undulatus, L. Pubescent ; stem racemose-panicled above ; leaves 

 varying from lanceolate to broadly ovate, often wavy or slightly serrate on 

 the margins, roughish on the upper surface ; the lowest on long and slender 

 petioles, wliich are dilated and clasping at the base ; the upper on broadly 

 winged petioles, or sessile and clasping ; scales of the obovoid involucre lin- 

 ear, appressed, acute. (A. scaber. Ell., with the smaller leaves very rough on 

 both sides.) — Woods, common and very variable. — Stem 2° - 3° high. Heads 

 small. Rays pale blue. 



•t- -1- Lowest leaves conspicuouslij serrate : heads small. 



22. A. eordifolius, L. Stem commonly smooth, racemose-panicled 

 above ; leaves smooth, or rough above and pubescent beneath, all cordate, 

 serrate, and slender-petioled, or the uppermo.st on short winged petioles, or 

 sessile and entire ; heads very numerous in panicled racemes; scales of the 

 obconical involucre loosely imbricated, with obtuse or slightly pointed green 

 tips. — Open woods, in the upper districts. — Stem l°-3° high. Leaves com- 

 monly thin. Rays pale violet. 



23. A. sagittifolius, Willd. Stem nearly smooth, racemose-branched 

 above; leaves ovate-lanceolate, acuminate, pubescent ; the lowest cordate, on 

 long and mostly margined petioles ; the upper abruptly contracted into a 

 winged petiole ; those of the branches lanceolate, acute at both ends, entire ; 

 heads in dense compound racemes; scales of the oblong involucre rather 

 loosely iml)ricated, linear-subulate, the tips green and spreading. — Rich 

 woods, Florida, and northward. — Stem 2° - 3° high. Heads more crowded 

 than those of the preceding. Rays purple. 



* 5. Leaves linear or lanceolate, entire, sessile ; radical ones spatulate-lanceolate, 

 serrate : heads small and numerous, racemed : scales of the involucre in several 

 rows, rigid, with spreading or recurved green tips. 



24. A. ericoides, L. Smooth ; stem much branched ; leaves linear-lan- 

 ceolate, acute at each end ; those of the branches subixlate ; heads racemose, 

 mostly on one side of the spreading branches ; scales of the involucre broadest 

 at the base, with acute or subulate tips. — Var. villosus. Stem and broader 

 leaves rough-hairy, and the smaller heads in shorter and more dense racemes. 

 — Var. PLATYPHTLLUS. Stem (3° -4°) and larger leaves clothed with soft 

 ■white hairs ; heads larger. — Dry soil, Florida, and northward. — Stem l°-2° 

 high. Rays white or pale blue. 



Var. Reevesii, Gray. Stem l°-2° high, branching from near the base ; 

 smooth, or papillose-hispid ; leaves linear, the lowest hispid-ciliate; heads 3"- 

 4" long, on tliickly bracted pedicels. — Nashville, Tennessee. 



25. A. polyphyllus, Willd. Nearly glabrous ; stem 4° -."5° high, much 

 branched ; leaves linear-lanceolate, long-acuminate, the lower sharply serrate, 

 3' -5' long; heads racemose at the end of tlie branches; involucre scales 

 linear or linear-subulate, appressed ; rays short, white. — North Carolina 

 {Gray), and northward. 



