THISTLE FAMILY 807 



Stem-leaves not cordate-clasping. 



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



or more. Xll. Asperi. 



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



mm. wide. ^ , , ^ 



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

 Danpus-bristles of the ray-flowers usually lacking; annuals. 



XIII. Kamosi. 

 Stems and leaves densely short-pubescent with spreading hairs; 



pappus-bristles of the ray-flowers present. 

 Aimuals; pappus scant and simple. XIV. Bellidiastra. 



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

 subulate squamellae. XV. Divergentes. 



Plants at first with a scapiform naked peduncle, later producmg rumier-like 

 branches X\l. Flageli^vres. 



Bracts of the involucre in 3^ series, more or less imbricate, thickened on the back, the 



outer usually successively shorter; perennials with cespitose caudices. 

 Rays bluish. purpHsh, or white. 



Achenes terete or nearly so. several -nerved. XV il. CAM. 



Achenes flattened or quadrangular, 2-4-nerved. ^^^ttt ^ 



Leaves more or less distinctly triple-nerved. X\ 111. CaespitosI. 



Leaves not triple-nerved. ,, ^,., , ^ i, ^i i* 



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

 rowly linear-oblanceolate ; heads solitary to few. 

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



Leaves narrowly linear-oblanceolate. 



Involucres glandular. XX. Arenartoides. 



Involucres liirsute or strigose. XXI. Laetevirextes. 



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

 * Leaves narrowly linear or linear-oblanceolate; achenes quadrangular, 

 4-nerved. XXII. Tetrapleuri. 



Leaves filiform; achenes flat. 2-nerved. "^ v^\r' l^^^^^o^^^- 



Rays yellow or ochroleucous. XXIV. LUTEI, 



I. Acres. 



Bracts of the involucre hnear. abruptly acute, never glandular; mner rayless pistUlate 



flowers rare; inflorescence strictly racemiform, with almost erect branches. 

 Low. 1-2 dm. high, usually branched at the base; stem-leaves sessUe; pedimcles short. 



not exceeding the subtending leaves. .. , ^ ^ ,-^", ^' ^^'^f;- ^ ^ 



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

 peduncles elongate. ^ ^ ,2 E, lonchophyllus. 



Bracts of the involucre linear-subulate, long-attenuate, and except m E. elalus more 



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



late, branches ascending. . , ^ i. 



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

 Bracts glandular-puberulent, rarely with a few hairs. , . t i 



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

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



® 3. E. poUtus. 



Base of the involucre sparingly hirsute ; leaves hairy, at least on the margins 

 and veins beneath; stem-leaves Unear or hnear-oblanceolate. 



4. E. droebachensis. 



Bracts hirsute or both hirsute and glandular-puberulent. . 



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



Bracts not glandular; leaves glabrous except the ciUate margins. 



6. E, clutus. 



Plant low. 1-3 dm. high, perennial; heads few or solitary. 



Involucres not black-hairy. - -r. . 



Involucres glandular and Mrsute. 7. K jucundus. 



Involucres villous, not glandular. 8. E. alptnus, 



iiiv.^x*» 9. £J. unalaschkensis. 



■hair\ 



Uniflori 



^'^&ef o1 ^^or^'less wide, erect; plant usually less tHan 1 dm bigh; leaves and 



ct^m rfVidedlv villous. ^ ^- unalaschkensis, 



T ieSes 1-1 5 mm. wide, spreading; plant about 1 dm. high; basal leaves glabrate; 



lower part of the stem strigose or glabrate. ^ , „ ^^ t 



Involucres and peduncles with black-purple hau^. 10. E. melanocephalus. 

 Involucres and peduncles white-hairy. 



Basal leaves sparingly hairy or glabrate. «;^n7^r 



Basal leaves spatulate, obtuse. 11- E. simplex. ^ 



Basal leaves narrowly linear-lanceolate. yii. -c.- ^crionen. 



Basal leaves densely villous. 



Stem 1-2 dm. high, leafy; basal leaves oblanceolate. often acutish. 



Stem 5-6 cm. high, scapiform; basal leaves cxmeate-spatulate, often 3- 



toothed. J?' f ■ l<^riatus. 



^ . 1 «n«^ 14. E. aureus, 

 Ligides yellow- 



