THISTLE FAMILY 247 



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

 Involucre.s not black-hairy. 



Involucro-i glandular and hirsute. 7. E. jncundus 



Involucres villous, not glandular 8. E. alpinus. 



Involucre black-hairy. 9. E. unalaschkcnsis. 



* II. Uniflori. 



Ligules purple or white. 



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

 ^ stem decidedly villous. 9. E. unalaschkensis. 



Ligules 1-1.5 mrn. 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. 



Involucr&s and peduncles white-hairy. 



Basal leaves sparingly hairy or glabrate. 



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



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



Basal leaves densely villous. 



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



12. E. grandiflorus. 

 Stem 5-6 cm. high, scapiform : basal leaves cimeate-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 pinna tely divided. 



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



15. E. pinnatisectus. 

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



16. E. tnancus. 

 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 ape.x; d^isions 

 spatulate. 

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



lobes of the leaves spatulate. 1<S. E. trifidus. 



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

 the leaves linear. 19. E. pedatus. 



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



20. E. flabellifoUus. 



IV. RADIC.A.TI. 



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-oblunceolate. 21. E. leiomerus. 



Basal leaves spatulate. 22. E. spaihulif alius. 



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. controrersus. 

 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-pubejscent ; disk over 1 dm. liigh; 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 appre.ssed hairs, or glabrate. 



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



28. E. Erermannii. 

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



29. E. Peasei. 

 Stem Avith more or less spreading hairs. 



Stems decumbent or ascending; leaves spreading, either softly hairy 

 or glabrate in age. 

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

 outer pappus of small squamellae; rays white. 



30. E. radicalus 

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



long: rays purple. 31. E. retensis. 



Stems and leaves almost erect: the latter coarsely hirsute. 



Basal leaves narrowly linear-oblanceolate: stem-leaves linear. 



32. E. nanus. 



