194 COMPOSITJE. (composite PAIULY.) 



***** Leaves none of them heart-shaped ; tlwse of the stem tapering at the base, 

 sessile; involua-e imbricated ; the scales of unequal length, with short and narrow 

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

 pale bluish-purple. 



1- Heads small. (Involucre \' -^ long.) 



18. A. dumdsus, L. Smooth or nearly so, racemosely compound, the 

 scatte^-ed 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 imh-icated 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, and an inversely con- 

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

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

 peculiar forms. 



19. A. Xradescdnti, L. Smooth or smoothish ; the numerous heads dosdy 

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

 lanceolate-linear, elongated, the larger ones remotely sen-at»! in the middle with 

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

 in 3 or 4 rows. — Var. feXgilis has the leaves entire or nearly so, except tlie 

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

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

 Kays white or nearly so. 



20. A. miser, L., Ait. More or less hairy, m-ach branched; tlie branches 

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

 long-lanceolate, tapering or pointed at each end, sharply sarate 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 betv.-cen tliem, 

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



■<- 1- Heads middle-sized. [Involucre .{' - i' 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 sen'ote ; scales of the involucre linear-aid-shaped, 

 loosely aiul sparingly imbricated. — Siiady moist banks, common. — Kays pale. 

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



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

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

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

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

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

 Wisconsin, and southward. Kays short and narrow, pale pm-ple or whitish. 



23. A. CiirneilS, 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, abruptly acute, closely imbricated. — Moist soil; common. Leaves 

 firm in texture, smooth, or i lugh above. Rays rather large, bluish, purplish, 



