946 FLORA. 



Leaves entire, linear, spatulate, or obovate, rigid. 



Glabrous, or nearly so; leaves linear or linear-spatulate. i. ,5". linifolius. 



Puberulent or scabrous ; leaves obovate. 2. S. bifoliatus. 



Leaves dentate, oblong, or obovate, thin. 3. S. aster aides. 



1. Sericocarpus linifolius (L.) B.S.P. NARROW-LEAVED WHITE-TOPPED 

 ASTER. (I. F. f. 3732.) Glabrous or very nearly so throughout; stem rather slen- 

 der, striate, 3-5 dm. high. Leaves spreading, faintly 3-nerved, thick, obtuse at 

 the apex, narrowed at the base, 3-5 cm. long, 3-6 mm. wide, sessile, or the lowest 

 with short margined petioles, their margins scabrous; heads about 6-8 mm. high, 

 clustered in 2's-6's at the ends of the cymose branches; involucre oblong-campan- 

 ulac, its bracts oblong, obtuse, the outer with somewhat spreading or reflexed 

 green tips, the inner scarious and often lacerate or ciliate at the apex; rays 4 or 5, 

 8-IO mm. long; pappus white. In dry, usually sandy soil, Canada, Vt. to Ohio, 

 Ga. and La. June-Sept. [S. soKdagineus Nees.J 



2. Sericocarpus bifoliatus (Walt.) Porter. ROUGH WHITE-TOPPED ASTER. 

 RATTLESNAKE MASTER. (I. F. f. 3733.) About 6 dm. high, the stem terete, or 

 slightly angled. Leaves sessile, obscurely veined, thick, obtuse, ascending or erect 

 by a twist at the base, 1-2.5 cm - l n g? 8-16 mm. wide, mucronulate, densely 

 appressed-puberulent on both sides, the upper mostly oblong, much smaller; -heads 

 8-10 mm. high, cymose-paniculate; involucre narrowly campanulate, its bracts 

 oblong or the inner linear, pubescent, their tips somewhat spreading; rays short; 

 pappus white. In dry soil, Va. to Fla. and La., mainly near the coast. July- 

 Sept. 



3. Sericocarpus asteroides (L.) B.S.P. TOOTHED WHITE-TOPPED ASTER. 

 (I. F. f. 3734.) Stem pubescent, or glabrate, slightly angled, 3-6 dm. high. 

 Leaves pubescent or glabrous, ciliate, the basal and lower ones obovate or spatulate, 

 dentate or rarely entire, 5-10 cm. long, 5-35 mm. wide, narrowed into margined 

 petioles; upper leaves oblong or oblong-lanceolate, entire or dentate, acute or ob- 

 tuse, smaller; heads 10-12 mm. high, densely clustered; involucre campanulate, 

 its bracts oblong, ciliate or pubescent, the outer with green reflexed tips; pappus 

 brown or white. In dry woods, Me. to Fla., Ohio, Ky. and Ala. July-Sept. 



31, ASTER L.* (See Appendix.) 



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

 corymbose or paniculate (rarely racemose or solitary) heads of both tubular and 

 radiate flowers. Involucre hemispheric, campanulate or turbinate, its bracts vari- 

 ous, 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, usually 

 in I series, sometimes in 2 series. Achenes mostly flattened and nerved. [Greek, 

 star.] A genus of not less than 250 species, most abundant in N. Am. where, 

 in addition to the following, about 70 others occur beyond our limits. The species 

 are very variable, as is expressed in the large number of subspecies here admitted. 



A. Basal and lower leaves, or some of them, cordate and slender-petioled. (See No. 52.) 

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



* Rays white, violet or rose. 



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



f Involucre ovoid, campanulate or turbinate, its bracts mostly obtuse or rounded; basal 



leaves few and small, or commonly none (except in No. 6). 



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



Heads 18 mm. broad or less, the disk turning crimson; leaves acute or short-acuminate, 

 chiefly crenate-serrate. i. A. carmesinus. 



Heads 18 mm. broad or more, the disk turning brown or reddish brown; leaves long- 

 acuminate, sharply serrate. 



Heads 18-25 mm. broad ; leaves of the branches small, obtuse, or acute. 



2. A. divaricatus* 



* Prepared with the assistance of Prof, EPWARD S, BURGESS, 



