COMPOSITE. (COMPOSITE FAMILY.) 233 



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. Kays mostly short, pale bluish-purple or 

 white. 



-t- -i- Heads middle-sized. (Involucre 3" -5" long.) 



22. 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 linear-aid-shaped, 

 loosely and sparingly imbricated. — Shady moist banks : common. — Rays pale. 

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



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

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

 tapering into a long slender point (2'- 6' long), with rough margins, tlie lower 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. Rays short and narrow, pale purple or whitish. 



24. A. cameus, 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 in- 

 volucre lanceolate, abruptly acute, closely imbricated. — Moist soil : common. Leaves 

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

 violet-purple, or almost white. — On a thorough revision of the genus, older 

 names will be found and verified for this and No. 22, which here cover a multi- 

 tude of forms. A mutabilis, L., is probably one of them. 



****** Stem-leaves sessile, the upper more or less clasping : scales of the hemi- 

 spherical involucre loosely more or less imbricated, somewhat equal, with herba- 

 ceous tips, or the outer often entirely herbaceous : heads middle-sized or large : 

 rays blue or purple. (The species of this group are still perplexing.) 



25. A. sestivus, Ait. Stem slender, rough, bushy-branched ; leaves nar- 

 rowly lanceolate-linear, elongated, taper-pointed, entire, with rough margins ; heads 

 corymbose, loose ; scales of the involucre linear, loose ; rays large, apparently light 

 blue. (A. laxifolius, Nees.) — Var. l.«tiflukus has very slender branches 

 and leaves, and the scales of the involucre unequal and more appressed. — 

 Moist shady places, Ohio to Wisconsin and northward. — Heads about as large 

 as in A. puniceus, in some forms appearing more like A. carneus. Leaves 4'- 

 V long, %' to £' wide. 



26. A. Novi-Belgii, L. Nearly smooth ; stem stout ; leaves oblong-lanceo- 

 late, pale or somewhat glaucous, serrate in the middle, acute, tapering to each end ; 

 scales of the involucre rather closely imbricated, with broadish acute herbaceous tijis: 

 rays pale blue or purplish. — Low grounds, not clearly known in a wild state. 

 The plant here in view is intermediate between No. 24 and No. 27. — Heads 

 smaller and less showy than in the next. 



27. A. longif61ius, Lam. Smooth or nearly so ; stem branched, corym- 

 bose-panicled at the summit ; leaves lanceolate or linear, or the lower ovate-lanceo- 

 late, entire or sparingly serrate in the middle, taper-pointed, shining above; scales 



