COMPOSITE. (COMPOSITE FAMILY.) 231 



acute green tips tapering down on the midnerve. (A. laevis, L. A. laevigatus, 

 Willd.} Dry woodlands : rather common. 



Var. ey&neus. Very smooth, but pale or glaucous ; leaves thicker ; the 

 upper often oblong or ovate-lanceolate, clasping by a heart-shaped base ; invo- 

 lucre narrowed at the base, of broader and more coriaceous scales with shorter 

 and abrupt tips. (A. cyaneus, Hofftn., frc.} Border of woodlands : common, 

 especially northward. 



11. A. turbindllus, Lindl. Very smooth; stem slender, paniculately 

 branched ; leaves lanceolate, tapering to each end, entire, with rough margins ; 

 involucre elongated-obconical or almost club-shaped (^' long) ; the scales linear, 

 with very short and blunt green tips ; rays violet-blue ; achenia nearly smooth. 

 Dry hills, &c., Illinois and southwestward. Well-marked and handsome. 

 * # * Lower leaves all heart-shaped and petioled, the upper sessile or petioled : invo- 

 lucre imbricated much as in the last division, but the heads smaller, very numerous, 

 racemosed or panicled. 

 *- Leaves entire or slightly serrate : heads middle-sized : rays bright-blue. 



12. A. azureus, Lindl. Stem rather rough, erect, racemose-compound 

 at the summit, the branches slender and rigid ; leaves rough ; the lower ovate-lance- 

 olate or oblong, heart-shaped, on long often hairy petioles ; the others lanceolate or lin- 

 ear, sessile, on the branches awl-shaped ; involucre inversely conical. Copses 

 and prairies, Niagara Falls (Clinton), and Ohio to Wisconsin and southward. 

 Involucre much as in A. laevis, but much smaller, slightly pubescent ; the rays 

 bright blue. 



13. A. Shortii, Boott. Stem slender, spreading, nearly smooth, bearing 

 very numerous heads in racemose panicles ; leaves smooth above, minutely pubes- 

 cent underneath, lanceolate or ovate-lanceolate, elongated, tapering gradually to a 

 sharp point, all but the uppermost more or less heart-shaped at the base, and on naked 

 petioles ; involucre bell-shaped. Cliffs and banks, Ohio to Wisconsin and 

 southward. A pretty species, 2 -4 high ; the leaves 3' - 5' long. 



14. A. undulatus, L. Pale or somewhat hoary with close pubescence ; 

 stem spreading, bearing numerous heads in racemose panicles ; leaves ovate or 

 ovate-lanceolate, with wavy or slightly toothed margins, roughish above, downy under- 

 neath, the lowest heart-shaped on margined petioles, the others abruptly contracted 

 into short broadly winged petioles which are dilated and clasping at the base, or di- 

 rectly sessile by a heart-shaped base ; involucre obovoid. (A. diver sifcjjius, 

 Michx.) Dry copses : common. 



-- 1- Leaves conspicuously serrate : heads small: rays pale blue or nearly white. 



15. A. COrdif61ius, L. Stem much branched above, the spreading or di- 

 verging branches bearing very numerous panicled heads; lower leaves all heart- 

 shaped, on slender and mostly naked ciliate petioles ; scales of the inversely coni- 

 cal involucre all oppressed and tipped with short green points, obtuse or acutish. 

 Woodlands: very common. Varies with the stem and leaves either smooth, 

 roughish, or sometimes hairy. Heads profuse, but quite small. 



16. A. sagittifdlius, Willd. Stem rigid, erect, with ascending branches 

 bearing numerous racemose, heads ; leaves ovate-lanceolate, pointed ; the lower 

 heart-shaped at the base, on margined petioles ; the upper lanceolate or linear, 



