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. 



*- - 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 sen-ate ; scales of the involucre linear-awl-shaped, 

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

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



23. A. tenuifblius, 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-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. C&rneilS, 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. SBStivus, 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^TiFL6RUS 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' - 

 7' long, y to ' wide. 



26. A. Novi-B^lgii, L. Nearly smooth ; stem stout; leaves oblong-lanceo- 

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

 scales of the involucre rather closely imbricated, with broadish acute herbaceous tips ; 

 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. longif61iU8, 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 



