192 COMPOSITE, (composite familt.) 



* # I/ywer leaves not heaH-shaped ; the upper all sessile and more or less clasping hy 

 a heart-shaped or auricled hose : heads showy : scales of the inversely conical or hell- 

 shaped involucre regularly imhicated in several rows, the outer successively shorter, 

 oppressed, coriaceous, whitish, loith short herbaceous tips :■ rays large, purple or blue. 



8. A. patens, Ait. Rough-pubescent; stem loosely panicled above {!"- 3° 

 high), with widely spreading branches, the heads mostly solitary, terminating 

 the slender branchlets ; leaves oblong-lanceolate or ovate-oblong, often contracted 

 below the middle, all clasping by a deep auricled-heart-sliaped base, rough, especially 

 above and on the margins, entire ; scales of the minutely roughish involucre 

 with spreading pointed tips; achenia silky.' — Var. puLOGirbLios is a foim 

 wliich the plant assumes in shady moist places, with larger and elongated thin 

 scarcely rough leaves, downy undenieath, sometimes a, little toothed above, 

 mostly much contracted below the middle. — Dry ground, common, especially 

 southward. Heads ^' broad, and with showy deep blue-purple rays, 



9. A. Iftvis, L. Very smooth throughout; heads in a close panicle ; leaves 

 thickish, lanceolate or ovate-laaceolate, chiefly entire, the upper more or Icfs 

 clasping by an auricled or heart-shaped base ; scales of the short-oboroid or heini 

 splierical involucre with appressed green points ; rays sky-blue ; achenia smooth. A 

 variable species, of which the two best-marked forms are : — 



Var. lievigutus. Scarcely if at all glaucous; leaves lanceolate or ob 

 long; involucre nearly hemispherical; the scales lanceolate or linear, with nar 

 row and acute green tips tapering down on the midnerve. (A. liEvis, L. A. 

 IsBvigatus, Willd.) — Dry woodlands ; rather common. 



Var. cyaneus. Very smooth, but pale or glaucous ; leaves thicker ; the 

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

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

 and abrupt tips. (A. cyaneus, Hoffm., ^c.) — Border of woodlands ; common, 

 especially northward. — A very elegant species, with showy flowers. 



10. A. tlirbincllUS, Lindl. Very smooth ; stem slender, paniculatclj 

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

 volucre elongated-obconical or almost club-shaped (J' long) ; the scales linear, with 

 very short and blunt green tips; rays violet-blue; acltenia nearly smooth. — Riv- 

 er-banks, Illinois and southwestward. 



* * # Lowei- leaves all htart-sliaped ami petioled, the upper sessile or petioled: invo 

 lucre iwbrieated inuch as in the last division, but the lieads smaller, very numerous, 

 racemose or panicled. 



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



11. A. a.zui'eus, Lindl. Stem rather rough, erect, racemose-compound 

 at the summit, the branches slender and rigid ; leaves rough ; the lower m:afe-larice- 

 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, Ohio to Wisconsin and southward. — A handsome species ; the in- 

 volucre much as in No. 9, but much smaller, and slightly pubescent ; the rays 

 bright blue. 



12. A. Shdrtii, Boott. Stem slender, spreading, nearly smooth, bearing 

 veiy numerous heads in racemose panicles ; leaves sfinooth above, minutely pubescent 



