246 CARD U ACE AE 



Stem leafy, 2-10 dm. high, if lower bearing several heads; stem-leaves 

 ample. 

 Steins densely cespitose from a thick taproot; heads small, the 

 disk rarely more than 1 cm. wide. 

 Pappus double; stem liirsute. V. Pumili. 



Pappus simple: stems strigose. VI. Decu.mben'TES. 



Stems usually solitary from the ends of distinct (sometimes branched) 

 rootstocks; heads large, the disk more than 1 cm. wide. 

 Bracts with loose tips; rays broad; pappus simple; lower leaves 

 broadly oblanceolate, the upper often reduced. 

 Bracts villous. VII. El.\tiores. 



Bracts glandular-puberulent or glabrous. 



VIII. S.\LSUGINOSI. 



Bracts appressed, except the very tips; rays narrow; pappus 

 double; perennials with short rootstocks. 

 Upper stem-leaves ample, ovate to lanceolate, not much 

 smaller than the lower, wliich are more or less distinctly 

 3-nerved; peduncles usually short, ascending. 



IX. M.\CR.\XTHI. 



Upper stem-leaves reduced, linear-lanceolate; none of the 

 leaves 3-nerved; pedimcles long and erect. 



X. Gl.\belli. 

 Annuals or biennials, or perennials by means of stolons and offsets. 

 Stem-leaves broad, cordate-clasping; perennials with offsets. 



XI. PHIL.\DELPHiri. 



Stem-leaves not cordate-clasping. 



Stems rather simple, with a few large heads; disks about 1 cm. broad 



or more. XII. Asperi. 



Stems much branched, leafy, with numerous small heads; disk 6-9 

 mm. wide. 

 Stems strigose or sparingly hirsute except at the base, or glabrous ; 

 pappus-bristles of the raj'-flowers usually lacking; annuals. 



XIII. R.UIOST. 



Stems and leaves densely short-pubescent with spreading hairs; 

 pappus-bristles of the ray-flowers present. 

 Annuals; pappus scant and simple. XIV. Bellidi.vstr.v. 



Biennials (rarely perennials) ; pappus double, the outer of short 

 subulate sqtiamellae. XV. Diverge.vtes. 



Plants at first with a scapiform naked peduncle, later producing runner-Uke 

 branches. XVI. Fl.\gell.\re-5. 



Bracts of the involucre in 3—4 series, more or le.ss imbricate, thickened on the back, the 

 outer usually successively shorter; perennials with cespitose caudices. 

 Rays bluish, purpUsh, or white. 



Achenes terete or nearly so, several-nerved. XVII. C.wi. 



Achenes flattened or quadrangular, 2-4-nerved. 



Leaves more or less distinct^' triple-nerved. XVIII. C.\E-iPiT03l. 



Leaves not triple-nerved. 



Plants low, 2 dm. or less high; basal leaf-blides from broadly oval to nar- 

 rowly linear-oblanceolate; heads solitary to few. 

 Basal leaf-blades broadly oval or obovate. XIX. ASPERUGIXEI. 



Leaves narrowly linear-oblanceolate. 



Involucres glandular. XX. Arex.vrioides. 



Involucres hirsute or strigose. XXI. L.\ErEViRExrE3. 



Plant taller, 3-4 dm. liigh; leaves filiform or narrowly linear. 



Leaves narrowly linear or Unear-oblanceolate; achenes quadrangular, 



4-nerved. XXII. Tetr VPLEURI. 



Leaves filiform; achenes flat, 2-nerved. XXIH. Filieolii. 



Rays yellow or ochroleucous. XXIV. LurEi. 



I. Acres. 



Bracts of the involucre hnear, abruptly acute, never glandular; inner rayless pistillate 

 flowers rare; inflorescence strictlj- racemiform, with almost erect branches. 

 Low, 1-2 dm. high, usually branched at the base; stem-leaves sessile: peduncles short, 



not exceeding the subtending leaves. 1. E. minor. 



Taller, 3-6 dm. high, simple; lower stem-leaves petioled; basal leaves oblanceolate; 

 peduncles elongate. 2. E. lonchopliyllus. 



Bracts of the involucre linear-subulate, long-attenuate, and except in E. elatus more 

 or less glandular-puberulent; inflorescence incUned to be corymbiform or panicu- 

 late, branches ascending. 

 Plant tall, 3-8 dm. liigh, apparently only biennial: heads numerous, corymbose. 

 Bracts glandular-puberulent, rarely with a few hairs. 



Base of the involucre merely Klandular-puberulent; whole plant glabrous or 

 the margins of the leaves sparingly ciliate; stem-leaves lanceolate. 



3. E. politus. 



Base of the involucre sparingly liirsute: leaves hairy, at least on the margins 

 and veins beneath; stem-leaves linear or linear-oblanceolate. 



4. E. droebachensis. 

 Bracts hirsute or both hirsute and glandular-puberulent. 



Bracts both glandular-puberulent and hirsute; leaves more or less hairy. 



.5. E. yellowstonensis. 

 Bracts not glandular: leave~s glabrous except the ciliate margins. 



6. E. elatus. 



