260 COMPOSURE. (COMPOSITE FAMILY.) 



28. A. COncinnus, Willd. Not glaucous, slender, 1-3 high; leave^ 

 lanceolate, mostly somewhat serrate, the lowest spatulate-lanceolate on winged 

 petioles; heads smaller than in the preceding, numerous, panicled ; rays violet. 

 Rare ; Penn. and southward. 



H. -M- Rays white or turning purplish ; scales narrow, subulately green-tipped ; 

 leaves mostly narrow, narrowed at base, on the branchlets lax and attenuate. 



29. A. pOlyph^llUS, Willd. Often tall (4 or 5 high), with virgate 

 branches ; cauline leaves narrowly lanceolate or linear, 4 or 5' long ; heads 

 paniculate ; scales lanceolate-subulate, the outermost much shorter ; rays 4" 

 long. N. Vt. to Wise., and southward. Heads larger and flowering earlier 

 than the next. 



30. A. ericoides, L. Smooth or sparingly hairy (1-3 high) ; the sim- 

 ple branchlets or peduncles racemose along the upper side of the wand-like 

 spreading branches ; lowest leaves oblong-spatulate, sometimes toothed ; the 

 others linear-lanceolate or linear-awl-shaped ; heads 3" high or less ; involucral 

 scales often nearly equal, with attenuate or awl-shaped green tips. Dry open 

 places, S. New Eng. to Minn., and southward. Var. viLL6sus, Torr. & Gray, 

 is a hairy form, often with broader leaves ; chiefly in the Western States. 

 Var. pusf LLUS, Gray, is a dwarf slender and glabrous form of the barrens of 

 Lancaster, Penn. (Porter), with very narrow or filiform leaves and very small 

 few-flowered heads. Var. PR* NGLEI, Gray, a low strict form, with few erect 

 branches and rather small heads. About Lake Champlain. 



- - Hoary-pubescent or hirsute; herbaceous tips of the involucral scales squar- 

 rose or spreading ; cauline leaves small, linear, entire, scarcely narrowed at 

 the sessile or partly clasping base ; heads numerous, small, racemose. 



31 . A. ameth^stinus, Nutt. Tall (2 - 5 high), upright, much branched, 

 puberulent or somewhat hirsute ; leaves not rigid ; heads 3" high, the tips of 

 the scales merely spreading; rays light clear blue. Moist grounds, E. Mass, 

 to 111. and Iowa. With the habit of n. 11. 



32. A. nmltifl6rus, Ait. Pale or hoary with minute close pubescence 

 (1 high), much branched and bushy ; the heads much crowded on the spread- 

 ing racemose branches ; leaves rigid, crowded, spreading, with rough or ciliate 

 margins, the uppermost passing into the spatulate obtuse scales; heads 2 -3" 

 long; rays white or rarely bluish, 10-20. Dry sandy soil; common. 



,_ ^_ H_ Scales glabrous, closely imbricated (the outer regularly shorter), not cori- 

 aceous, with short appressed green tips ; branches slender, divaricate or diver- 

 gent ; leaves lanceolate to subulate ; heads small (2 - 3" high) and numerous. 

 -M. Heads scattered, terminating minutely foliose slender branchlets. 



33. A. dumdsus, L. Smooth or nearly so, 1-3 high; leaves linea* 

 or the upper oblong, crowded, entire, with rough margins ; scales linear-spatu- 

 late, obtuse, in 4 - 6 rows. Thickets ; common. A variable species, loosely 

 branched, with small leaves, especially the upper, and an obconical or bell- 

 shaped involucre, with more abrupt green tips than any of the succeeding. 

 Rays pale purple or blue, larger than in n. 34. Runs into several peculiar forms. 



-* Heads racemosely unilateral upon very short minutely leafy branchlets. 



34. A. vimineilS, Lam. Smooth or smoothish, 2-5 high, bushy ; leaves 

 linear or narrowly lanceolate, elongated, the larger ones remotely serrate in 



