COMPOSITAE 319 



1. Sericocarpus asteroides (L. ) B.S.P. Toothed White-topped 

 Aster. (Man. p. 946 ; I. F. f. 3734.) In dry woods, Me. to Fla., Ohio, 

 Ky. and Ala. — Pennsylvania : Northampton ; Bucks ; Delaware ; 

 Chester ; Montgomery ; Lancaster ; Franklin ; Allegheny. 



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

 Topped Aster. (Man. p. 946; I. ¥. /. 3/32.) 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, mainly 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. 

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

 plants not glandular. 

 Involucre ovoid, canipanulate or turbinate ; bracts obtuse or rounded 

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

 q;lonieralHS. 

 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 pilcse 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. roscidiis. 



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. 



