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 : raijs 50 to 60 or more^ fully half -inch long, 

 purple. — From Colorado to the Saskatchewan and eastward. 



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

 form. 



8. A. Oblongifolius, Nutt, About 2 feet high : stem hirsute-pubescent, 

 very leafy, cori/mboseltj branched: leaves from narrowly oblong to broadly 

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

 scented, the linear bracts granulose-glandular and viscidulous : 7-aijs 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 5-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. 

 -J- Whole plant I'ery smooth and glabrous : heads rather large, shoioy, with firm 

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

 lets mosthf reduced to rigid subulate bracts : akenes glabrous. 



10. A. Isevis, 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 Avinged 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 Wj-o- 

 ming and northward. 



•1- ^- Heads rather small (3 or 4 lines high), thijrsoidly or corymbosely arranged ; 

 bracts rigid, narrow, ivith subulate green nearly erect tips: rays numerous, 

 bright ichite, 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 



