COMPOSIT.^. (cOMrOSITi: TAMILY.) 2.'31 



acute green tips tapering down on the midncrvc. (A. la; vis, />. A. Uuvigatus, 

 Wili'd.) — Dry woodlands: rather lonnnon. 4 



Var. cytincus. Very smooth, hut jjalc or glaucous ; leaves thicker ; tho 

 upper oltiMi ohlong or ovate-lanceolate, clasping hy a heart-shaped base; invo- 

 lucre narn)Wi'd at the base, of broader and more coriaceous scales with shorter 

 and abrupt tii)S. (A. eyaiieus, Iloffm., i^c.) — JJordcr of woodlands : connnon, 

 especially north wanl. 



11. A. tui'binellus, Lindl. Very smooth; stem slender, paniculately 

 brauiiud ; Intns hiiictohitc, tapering to each end, entire, with rough margins ; 

 ini-o'ucre dotiijdtcd-ohcouirdl or almost club-shaped (V^OHg); tli<^ scales linear, 

 with very short and blunt green tips ; rajs violet-blue ; uclienia ni.arly smooth. — 

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

 * * * Lower laives all heart-shaped and petioled, t/ie upper sissile or pelioled: invo- 

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

 racemos'd or paniclcd. 

 ■*- Lexivrs entire or sli(jhtlij serrate : heads middle-siz^d : rays briyltt-blue. 

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

 at the sunnnit, the branches slender and rigid ; leaves rough ; the lower ovate-iance- 

 elate or oblomj, heart-shajted, on lonfj ojlen 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. la;vis, but much snuillcr, slightly pubescent ; the rays 

 bright blue. 



1"5. A. Shortii, Boott. Stem .slender, spreading, nearly smooth, bearing 

 very numerous heads in racemose panicles; hares smooth aliore, minutily pubes- 

 ant underneath, lanceolate or ovate-lanceolate, elonr/ated, 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 bank-s Ohio to Wisconsin and 

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



14. A. undulktUS, r>. Pale or somewhat hoary with close pubescence; 

 stem spreading, bearing nunu'rous heads in racemose panicles ; leaves ovate or 

 ovate-lanceolate, with wavy or sliyhtly toothed man/ins, roiiyhish above, downy under- 

 neath, the lowest heart-siiaiH-d on margined jx-tioles, the others abruptly contracted 

 into short broadly wimjt-d petioles which arc dihitrd ami claspinr/ at the base, or di- 

 rectly sessile by a heart-shaped Ijase ; invohure obovoid. (A. diversif()liu3, 

 Michx.) — Dry copses: common. 



■i- ■*- Leans conspicuously serrate: heads small : rays pale blw or nearly white. 



1.'). A. COrdif61iuS, L. Stem much hnwKhvil above, the sprradiny or di- 

 venjimj branches beariny very num-rons pnnicled hca-ls ; lower leaves nil heart- 

 shaped, on slender and mostly naked ciliatc petioles ; scales of the inversily coni- 

 cal involucre all appra^srd and tipped with short ip-een fwints, dttuse or acntish. — 

 Woodlands: very cominon. — Varies with the stem and leaves cither smooth, 

 rougiiish, or sonivtiin s hairy. Heads profuse, but (piite small. 



IG. A. sagittifblius, Willd. Stem rigid, crec. with nscendiny branch's 

 beurinij numerous raccwosi- hnuls; leaves ovate-lanceolate, jiointed ; the lower 

 hcart-bhaijed at the base, on margined petioles ; the upper lanceolate or linear. 



