194 COMPOSITE. (COMPOSITE FAMII.I.) 



***** Leaves none of them heart-shaped ; those of the stem tapering at the bane, 

 sessile; involucre imbricated; the scales of unequal length, with short and juurora 

 oppressed or rather loose greenish tips : heads small or middle-sized : rays white or 

 pale bluish-purple. 



- Heads small. (Involucre ' - 4' long.) 



18. A. cliliiiosus, L. Smooth or nearly so, racemoscly compound, the 

 scattered heads mostly solitary at the end of the spreading branchlets ; leaves linear 

 or the upper oblong, crowded, entire or slightly serrate, with rough margins ; 

 scales of the closely imbricated involucre linear-spatulate, obtuse, in 4-6 rows. 

 Thickets, in dry or moist soil; common. A variable species, l-3 high, 

 loosely branched, with small leaves, especially the upper, arid an inversely con- 

 ical or bell-shaped involucre, with more abrupt green tips than any of the suc- 

 ceeding. Rays pale purple or blue, larger than in the next. Runs into several 

 peculiar forms. 



19. A. TratleSClillti, L. Smooth or smoothish; the numerous heads closely 

 racemed along one side of the erect-spreading or diverging branches ; leaves 

 lanceolate-linear, elongated, the larger ones remotely serrate in the middle with 

 fine sharp teeth ; scales of the involucre narrowly linear, acute or acutish, imbricated 

 in 3 or 4 rows. Var. FRAGILIS has the leaves entire or nearly so, except the 

 lowest, and the heads more scattered. Moist banks, &c., very common. 

 Stems 2 -4 high, bushy: heads very numerous, smaller than in the last. 

 Rays white or nearly so. 



20. A. miser, L., Ait. More or less hairy, much branched ; the branches 

 usually diverging, bearing racemose often scattered heads; leaves lanceolate or ob- 

 long-lanceolate, tapering or pointed at each end, sharply serrate in the middle; 

 scales of the involucre linear, acute or rather obtuse, imbricated in 3 or 4 rows. 

 Thickets, fields, &c., very common, and extensively variable. Leaves larger 

 than in either of the preceding (2' - 5') ; the involucre intermediate between them, 

 as to the form of the scales. Rays mostly short, pale bluish-purple or white. 



- *- Heads middle-sized. (Involucre %' - $' long.) 



21. A. simplex, Willd. Smooth or nearly so (3 -6 high), much 

 branched ; the branches and scattered heads somewhat corymbose at the summit ; 

 leaves lanceolate, pointed, the lower serrate ; scales of the involucre lincar-awl-shaped, 

 loosely and sparingly imbricated. Shady moist banks, common. Rays pale. 

 Approaches in its different forms the preceding and the two following. 



22. A. tenuifolillS, L. Nearly smooth ; stem much branched (2 -3 

 high) ; the heads somewhat panicled or racemed ; leaves narrowly lanceolate, 

 tapering into a long slender point (2' -6' long), with rough margins, the lower some- 

 what serrate in the middle ; scales of the hemispherical involucre linear-awl-shuped, 

 very slender-pointed, numerous, closely imbricated. Low grounds, New York to 

 Wisconsin, and southward. Rays short and narrow, pale purple or whitish. 



23. A, ciiriieus, Nees. Smooth, or the branches rough or pubescent; 

 leaves lanceolate, somewhat pointed, or the upper short and partly clasping; 

 heads racemose along the ascending leafy branches ; scales of the obovate invo- 

 lucre lanceolate, abiitptly acute, rloseli/ imbricated. Moist soil ; common. Leaves 

 firm in texture, smooth, or ) ugh above. Kays rather large, bluish, purplish. 



