354 



COMPOSITAE. 



[Vol. Ill, 



2. Sericocarpus bifoliatus (Walt.) 



Porter. Rough White-topped Aster. 



(Fig- 3733-) 



Conyza bifoliata Walt. Fl. Car. 204. 1788. 

 Aster tortifolius Michx. Fl. Bor. Am. 2: 109. 1803. 

 5". tortifolius Nees, Gen. & Sp. Ast. 151. 1832. 

 5. bifoliatus Porter, Mem. Torr. Club, 5: 322. 1S94. 



Densely puberulent or scabrous, about 2 

 high, the stern terete, or slightly angled. Leaves 

 sessile, obscurely veined, obovate or broadly 

 spatulate, thick, obtuse, ascending or erect by a 

 twist at the base, % f -\ r long, 4 // -S // wide, en- 

 tire, mucronulate, densely appressed-puberulent 

 on both sides, the upper mostly oblong, much 

 smaller; heads 4 // ~5 // high, cymosc-paniculate; 

 involucre narrowly campanulate, its bracts ob- 

 long or the inner linear, pubescent, their tips 

 somewhat spreading; rays short; pappus white. 



In dry soil, Virginia to Florida and Louisiana, 

 mainly near the coast. Called also Rattlesnake- 

 master. July-Sept. 



3. Sericocarpus asteroides (L,.) 



B.S.P. Toothed White-topped Aster. 



(Fig. 3734.) 



Conyza asteroides L. Sp. PI. 861. 1753. 



.S". couyzoides Nees, Gen. & Sp. Ast. 150. 1832. 



.S". asteroides B.S.P. Prel. Cat. N. Y. 26. 1888. 



Stem pubescent, or glabrate, slightly angled, 

 l-2 high. Leaves thin, pubescent or gla- 

 brous, ciliate, pinnately veined and faintly 

 3-nerved, the basal and lower ones obovate or 

 spatulate, dentate or rarely entire, 2 '-4' long, 

 x'-yYz' wide, narrowed into margined petioles; 

 upper leaves oblong or oblong-lanceolate, en- 

 tire or dentate, acute or obtuse, smaller; heads 

 5 // -6 // high, densely clustered; involucre 

 campanulate, its bracts oblong, ciliate or 

 pubescent, the outer with green reflexed tips; 

 pappus brown or white. 



In dry woods, Maine to Florida, west to Ohio, 

 Kentucky and Alabama. July-Sept. 



31. ASTER L> Sp. PI. 872. 1753.* 

 Perennial or rarely annual, mostly branching herbs, with alternate leaves, and corym- 

 bose or paniculate (rarely racemose or solitary) heads of both tubular and radiate flowers. 

 Involucre hemispheric, campanulate or turbinate, its bracts various, imbricated in several 

 series, the exterior ones usually smaller and shorter. Receptacle flat or convex, generally 

 foveolate. Ray-flowers white, pink, purple, blue, or violet, pistillate. Disk-flowers tubular, 

 perfect, their corollas 5-lobed, usually yellow and changing to red, brown, or purple. 

 Anthers obtuse and entire at the base. Style-branches flattened, their appendages subulate, 

 lanceolate or ovate, acute. Pappus-bristles slender, numerous, scabrous or denticulate, usu- 

 ally in 1 series, sometimes in 2 series. Achenes mostly flattened and nerved. [Greek, star.] 

 A genus of not less than 250 species, most abundant in North America, where, in addition to 

 the following, about 70 others occur beyond our limits. Known as Asters or Starworts. 



A. Basal and lower leaves, or some of them, cordate and slender-petioled. (See No. 50.) 



1 . None of the stem-leaves cordate-clasping. 



jf Rays white, violet, or rose. 



\ Rays white, or rarely rose, usually 2-toothed; plants not glandular. 



I Involucre ovoid, campanulate or turbinate, its bracts mostly obtuse or rounded; basal leaves few 



and small, or commonly none (except in No. 5). 



(a) Leaves membranous or thin, smooth, or nearly so. 



Heads short-peduncled, 9" broad or less, the disk turning crimson; leaves acute or short-acuminate. 



1. A. carmesinus. 

 Heads long-peduncled, 9" broad or more, the disk turning brown or reddish brown; leaves long- 

 acuminate. 



Heads 1' broad or more; leaves of the branches large, long, lanceolate, acuminate. 



2. A. tenebrosus. 

 Heads ^"-ii" broad; leaves of the branches small, obtuse, or acute. 3. A. divaricatus. 



* Text prepared with the assistance of Prof. Edward S. Burgess. 



