COMPOSITE. (COMPOSITE FAMILY.) 161 



iower spatulate-linear, 2 to 4 inches long, 1 to 3 lines wide ; radical spatulate : 

 heads broad : involucral bracts linear-subulate ; outer little shorter than inner. 



— Proc. Am. Acad. xvi. 99. A. ericoides, var. striclus, Porter, Fl. Colorad. 56. 

 Common in the Colorado Rocky Mountains. 



*-*-■*- The numerous small heads racemosely arranged : unequal bracts well 

 imbricated, with squarrose or at least spreading herbaceous obtuse or merely ma- 

 cronate tips : cauline leaves small, linear and entire, scarcely narrowed at the 

 abrupt sessile or partly clasping base : akenes canescent-hirsute :. rays white, 

 rarely tinged with blue or purple. 



12. A. multiflorus, Ait. Low, a foot or two high, bushy-branched, 

 cinereous or green : leaves rigid, scabrous-ciliate ; uppermost passing into in- 

 volucral bracts ; these mostly with obtuse tips : heads in the ordinary forms 

 little' over 2 lines long, and with only 10 to 15 or 20 rays. — From Arizona to 

 British Columbia and eastward across the continent. 



13. A. COmmutatUS. A foot or so high, with divergent branches : 

 heads more scattered and twice or even thrice the size of those of A. multiflorus, 

 3 or 4 lines high and broad : rays 20 to 30 : otherwise nearly as the preceding. 

 — From Saskatchewan and the Dakotas to Utah and E. Oregon. 



4- *_ -i- h- Involucre in some imbricated and with short close tips, in others more 

 loose and herbaceous : heads when numerous either thyrsoid or open-paniculate 

 on erect or ascending branches. 



++ Cauline leaves sessile, but neither with cordate or auriculate base ( with 1 or 2 

 exceptions), nor with abrupt winged petiole-like lower portion. 



— Herbage inclined to be glabrous ; the branches often pubescent in lines : leaves 

 (at least some of them) serrate or denticulate: stems branching and with sev- 

 eral to many heads : none alpine or subalpine : Eastern forms. 



a. Involucre close and erect; its bracts imbricated in successive lengths. 



14. A. panieulatUS, Lam. Stem 2 to 8 feet high, freely and panicu- 

 lately branched : leaves from elongated oblong to narrowly lanceolate, mostly 

 attenuate-acuminate, sharply serrate or denticulate, or upper entire, thin: heads 

 about J inch high, in loose and open mostly leafy panicles : bracts of the invo- 

 lucre narrowly linear, with tapering acute or acuminate green tips : rays 3 or 4 

 lines long, white varying to purplish or violet. — A very polymorphous species, 

 including also part of the forms heretofore included under A. Tradescanti, 

 simplex, tenuifolius, and carneus. From E. Montana to Louisiana and east- 

 ward ; abundant in the Northeastern States. 



15. A. salieifolius, (Lam 1) Ait. Resembles the preceding, equally 

 branching : leaves commonly less elongated, less serrate or entire, of firmer tex- 

 ture, apt to be scabrous, and the fine reticulation of the veinlets manifest: 

 involucre more imbricated; its bracts firmer, linear, with shorter and more defi- 

 nite green tips, these acute or obtusish : heads disposed to be thyrsoid or racemose- 

 glomerate on the ascending branches : rays purplish to violet, rarely white. — 

 Includes A. carneus, in part. From E. Montana to Texas and northeastward ; 

 most abundant in the Mississippi Valley. 



b. Involucre loose, and less imbricated ; its bracts about equal. 



16. A. junceus, Ait. Slender, 1 to 3 feet high, the smaller plants sim- 

 ple-stemmed and with few heads, smooth and nearly glabrous : leaves linear or 



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