THISTLE FAMILY 247 



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

 Involucras not blaclc-halry. 



Involucres glandular and hirsute. 7. E. jucundus. 



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



Involucre black-hairy. 9. E. unalaschkensis. 



II. Uniflori. 

 Ligules purple or white. 



Ligules 0.5 mm. or less wide, erect; plant usually less than 1 dm. high; leaves and 

 stem decidedly villous. 9. E. unalaschkensis. 



Ligules 1-1.5 mm. wide, spreading; plant about 1 dm. high; basal leaves glabrate: 

 lower part of the stem strigose or glabrate. 

 Involucres and peduncles with black-purple hairs. 10. E. melanocephalus. 



Involucres and peduncles white-hairy. 



Basal leaves sparingly hairy or glabrate. 



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



Basal leaves narrowly linear-lanceolate. 92. E. Scribneri. 



Basal leaves densely villous. 



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



12. E. (irandiflorus. 

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

 toothed. 13. E. lanatus. 



Ligules yellow. 14. E. aureus. 



III. COMPOSITI. 



Leaves divided into linear or spatulate divisions ; plant with a cespitose caudex. 

 Leaves pinnately divided. 



Heads radiate; leaf segments rather distant; peduncles 5-20 cm. long. 



15. E. pinnatisectus. 

 Heads discoid ; leaf segments crowded ; peduncles 2-5 cm. long. 



16. E. mancus. 

 Leaves once to thrice ternately divided. ' 



Leaf-blades twice or thrice ternate. 17. E. compositus. 



Leaf-blades cuneate, ternately or pedate-quinnately cleft at the apex; divisions 

 spatulate. 

 Disk 10-15 mm. broad; bracts linear-subulate, scarcely scariouis-margined ; 



lobes of the leaves spatulate. 18. E. trifidus. 



Disk 7-10 mm. broad; bracts linear-lanceolate, scarious-margined ; lobes of 

 the leaves linear. 19. E. pedatus. 



Leaves ilabelliform, lobed or twice 3-cleft at the apex; plant with a creeping rootstock. 



20. E. flaheUifolius. 

 IV. Ramcati. 

 Head radiate. 



Involucre glandular-puberulent or glabrate, not hirsute. 



Stem and leaves glabrous or nearly so; involucres less than 12 mm. broad. 

 Basal leaves linear-oblanceolate. 21. E. leiomerus. 



Basal leaves spatulate. 22. E. spathulifolius. 



Stem and leaves pubescent; involucres 12-15 mm. wide. 



Stem and leaves hirsute. 63. E. viscidus. 



Stem strigose; leaves puberulent, especially on the margins. 



23. E. coniroversus. 

 Involucre more or less hirsute or strigose, in some also slightly glandular-puberulent. 

 Leaves and stem glandular scabrous as well as hirsute. 24. E. glandulosus. 

 Leaves and stem hirsute or strigose, rarely glandular. 



Stem 1 dm. or more high, appressed-pubescent; disk over 1 dm. high; branches 

 of the caudex or rootstock rather slender, often purplish. 

 Leaves narrowly linear-oblanceolate, 1-3 mm. wide, strigose. 

 Involucral bracts with appressed pubescence; rays purple. 



25. E. gracilis. 

 Involucral bracts with spreading pubescence. 26, E. Engelmannii. 

 Rays white; bracts narrowly linear. 

 Rays usually purplish ; bracts lance-linear. 

 Leaves oblanceolate to linear-oblanceolate, 3-8 mm. wide, glabrous above, 

 except the margins. 27. E. ursinus. 



Stem 4—7 cm. high; disk less than 1 cm. wide; caudex and its branches stout 

 and short, not purplish. 

 Leaves linear-oblanceolate to spatulate. 

 Stem with appressed hairs, or glabrate. 



Leaves and stem glabrous or nearly so; stem almost leafless. 



28. E. Bvermannii. 

 Leaves and stem distinctly strigose, the latter with several leaves. 



^ 29. E. Peasei. 



Stem with more or less spreading hairs. 



Stems decumbent or ascending ; leaves spreading, either softly hairy 

 or glabrate in age. 

 Pappus dpuble; inner pappus of 10-12 bristles, 2 mm. long; 

 outer pappus of small squamellae; rays white. 



30. E. radicatus. 

 Pappus simple or nearly so, consisting of many bristles, 3 mm. 

 long; rays purple. 31. E. veiensis. 



Stems and leaves almost erect; the latter coarsely hirsute. 



Ba.sal leaves narrowly Unear-oblanceolate ; stem-leaves linear. 



32. E. nanus. 



