COMPOSITAE 319 



1. Sericocarpus asteroides (L. ) B.S.P. Toothed WhiTE-Topped 

 Aster. (Man. p. 945 ; I. F. / 3734.) In dry woods, Me. to Fla., Ohio, 

 Ky. and Ala. — Pennsylvania : Northampton ; Bucks ; Dei,aware ; 

 Chester ; Montgomery ; Lancaster ; Frankun ; Ai,i,egheny. 



2. Sericocarpus linifolius (L.) B.S.P. Narrow-leaved White- 

 topped Aster. (Man. p. 946; I. P. /. 3732.) in dry, usually sandy 

 soil, Can., Vt. to Ohio, Ga. and La. — Pennsylvania: Delaware; 

 Bucks ; Chester ; Lancaster. 



13. ASTER L. 



A. Basal and lower cauline leaves with relatively broad blades,maitily of an 

 ovate or cordate type, and with long petioles, the upper cauline somewhat 

 similar but short-petioled or sessile. 

 a. Blades of the upper cauline leaves not cordate-clasping : petioles of the 

 lower cauline leaves not dilated-clasping. 

 Ray-flowers with white, pink or violet ligules. 

 Ligules of the ray-flowers white or occasionally pinkish, usually 2-toothed: 

 plants not glandular. 

 Involucre ovoid, campanulate or turbinate ; bracts obtuse or rounded 

 at the apex : basal leaves few and small, or wanting except in A. 

 glomeratus. 

 Leaf-blades thin-membranous, smooth or nearly so. 

 Leaf-blades mainly of an ovate-lanceolate type : leaves of the 



branches relatively short. i. A. divaricatus. 



Leaf-blades mainly of an oblong-lanceolate type : leaves of the 



branches relatively long. 2. A. tenebrosus. 



Leaf -blades thick, firm, rough, at least when dry. 



Leaf-blades acute or short-acuminate, pilose beneath : inflorescence 



glomerate. 3. A. glomeratus. 



Leaf-blades long-acuminate, not pilose beneath : inflorescence 

 open paniculate. 4. A. Claytonii. 



Involucre cylindric ; bracts tapering to an obtuse tip : basal leaves 

 large, tufted. 

 Bracts of the involucre pale, scarious, usually without herbaceous 



tips. 5- A. curvescens. 



Bracts of the involucre broader, with herbaceous tips. 



6. A. Schreberi. 

 Ligules of the ray-flowers violet, usually 3-toothed : plants glandular. 

 Most of the glands large, capitate : leaf-blades coarse and thick. 

 Glands mainly in the inflorescence : leaf-blades with a broad sinus : 



growing plant harsh. 7. A. macrophyllus. 



Glands abundant in the foliage : leaf-blades with a narrow sinus : 

 growing plant clammy. 8. A, roscidus. 



Most of the glands minute, scarcely capitate : leaf-blades mostly thin. 



9 A . multiformis. 

 Ray-flowers with blue or purple ligules. 

 * Leaf -blades thick or firm, entire or essentially so. 



Leaves of a firm or thick texture ; blades glabrous or nearly so above. 



10. A. Shortii. 

 Leaves of a spongy texture ; blades rough-puberulent. 



11. A. azureus. 



