160 COMPOSITE. (COMPOSITE family.) 



pubescence : leaves lanceolate or broadly linear, pubescent, 2 to 5 inches long, 

 entire, slightly if at all narrowed below, half-clasping by a strongly auricu- 

 late-cordate base: heads crowded: rays 50 to 60 or more, fully half-inch long, 

 purple. — From Colorado to the Saskatchewan and eastward. 



Var. roseus, DC. Kays rose-colored. — Occasionally with the ordinary 

 form. 



8. A. oblongifolius, Nutt. About 2 feet high : stem hirsnle-]iubescenl, 

 very leaf)', corymbosely branched : leaves from narrowly oblong to broadly 

 linear, larger cauline 2 inches long, somewhat puberuleut : involucre aromatic- 

 scented, the linear bracts granulose-glandular and viscidulous : rays 25 to 30, 

 bright violet, 5 or 6 lines long.. Hardly within our range, but represented in 

 Colorado by 



Var. rigidulus, Gray. Low, more fastigiate, with more rigid and 

 hispidulous scabrous leaves. — Synopt. Fl. i. 179. 



* * * Heads small, paniculate: lower cauline and radical leaves cordate and 



petioled : no glandular or viscid pubescence: akenes compressed, 3 to b-nerved : 

 rays violet, purplish, or white. 



9. A. sagittifolius, Willd. Green, from glabrous to sparsely pilose- 

 pubescent : stem strict, 2 or 3 feet high : leaves oblong- and ovate-lanceolate, 

 acutely more or less serrate; radical and lowest cauline narrowly cordate, on 

 naked petioles; upper subcordate or truncate at base and contracted into a 

 winged petiole, 3 to 5 inches long ; uppermost linear-lanceolate and sessile : 

 heads densely thyrsoid-paniculate : bracts of the involucre subulate-linear and 

 mostly attenuate, the tips rather loose. — In the Dakotas within the eastern 

 limit of our range, and extending eastward. 



* * * * No cordate petioled leaves; radical leaves all acute or attenuate at 



base : not glandular nor viscid nor silky-canescent : akenes compressed, few- 

 nerved. 

 *- If 7io/e plant very smooth and glabrous : heads rather large, showy, with firm 

 closely imbricated oppressed green-tipped bracts: leaves on flowering branch- 

 lets mostly reduced to rigid subulate bracts : akenes glabrous. 



10. A. lsevis, L. Rather stout, 2 to 4 feet high, rigid : leaves from ovate 

 or oblong to lanceolate, 4 or 5 inches long, decreasing upward ; radical and 

 lowest cauline contracted below into a winged petiole ; upper all with auricu- 

 late or subcordate partly clasping base : heads sparsely thyrsoid-paniculate, 

 on short and rigid branchlets: involucre campanulate or obscurely turbinate; 

 the whitish coriaceous bracts bearing abrupt rhomboid or deltoid short green 

 tips : rays 20 or 30, broadish, sky-blue verging to violet. — Eastern slopes of 

 the Rocky Mountains and eastward across the continent. 



Var. Geyeri, Gray. A foot or two high : involucre broader and less 

 imbricated ; its bracts of thinner texture, mostly attenuate-acute, the green 

 tip less definite. — Synopt. Fl. i. 183. In the mountains of Idaho and Wyo- 

 ming and northward. 

 +- i- Heads rather small (3 or 4 lines high), thyrsoidly or corymbosely arranged ; 



bracts rigid, narrow, with subulate green nearly erect tips: rai/s numerous, 



bright white, 4 lines long: akenes minutely pubescent. 



11. A. Porteri, Gray. A foot or less high, glabrous and smooth (except 

 ciliation of lowest leaves), either simple or branching above : leaves linear or 



