246 CARDUACEAE 



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

 ample. 

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

 disk rarely more than 1 cm. wide. 

 Pappus double; stem hirsute. V. Pumilt. 



Pappus simple; stems strigose. VI. Decumbentes. 



Stems usually soUtary 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. Elatiores. 



Bracts glandular-puberulent or glabrous. 



VIII. S.\USUGINOSI. 

 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, which are more or less distinctly 

 3-nerved; peduncles usually short, ascending. 



IX. Macranthi. 

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

 leaves 3-nerved; peduncles long and erect. 



X. Glabelli. 

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

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



XI. Philadelphici. 

 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 ray-flowers usually lacking; annuals. 



XIII. Ramost. 

 Stems and leaves densely short-pubescent with spreading hairs; 

 pappus-bristles of the raj;-flowers present. 

 Annuals; pappus scant and simple. XIV. Bellidiastra. 



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

 subulate squamellae. XV. Divebgentes. 



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

 branches. XVI. Flagellares. 



Bracts of the involucre in 3-4 series, more or less imbricate, tliickened on the back, the 

 outer usually successivelj^ shorter; perennials with cespitose caudices. 

 Rays bluish, purplish, or white. 



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



Achenes flattened or quadrangular, 2-4-nerved. 



Leaves more or less distinctly triple-nerved. XVIII. Caespitosi. 



Leaves not triple-nerved. 



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

 rowly linear-oblanceolate ; heads soUtary to few. 

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



Leaves narrowly Unear-oblanceolate. 



Involucres glandular. XX. Arenarioides. 



Involucres hirsute or strigose. XXI. Laetev'irbnte3. 



Plant taller, 3-4 dm. high; leaves flliform or narrowly Unear. 



Leaves narrowly linear or linear-oblanceolate; achenes quadrangular, 



4-nerved. XXII. TETR.VPLECRI. 



Leaves flliform; achenes flat, 2-nerved. XXIII. FIUPOLII. 



Rays yellow or ochroleucous. XXIV. Lutei. 



I. Acres. 



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

 flowers rare; inflorescence strictly 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. lonchophyllus. 



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

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

 late, branches ascending. 

 Plant tall, 3-8 dm. high, apparently only bieimial; heads numerous, corymbose. 

 Bracts glandular-puberulent, rarely with a few hairs. 



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

 the margins of the leaves sparingly cihate; 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. jE. drocbaclicnsis. 

 Bracts hirsute or both hirsute and glandular-puberulent. 



Bracts both glandular-puberulent and hirsute; leaves more or Ic-f's hairy. 



.5. E. ycllowslonensis. 

 Bracts not glandular; leaves glabrous except the ciliate marsins. 



0. IS. elatus. 



