564 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Leaves hispidulous, curved; rays 
pale yellow .......-..--.------- 5. E. curvifolius. 
Leaves canescent-puberulent, 
straight; rays bright yellow Leese 10. E. filifolius. 
Rays not yellow. 
Leaves cleft or parted. 
Leaves parted into narrow lobes.... 9. E. compositus. 
Leaves merely 3 to 5-cleft...-.-.--- 9a. E. compositus trifidus. 
Leaves entire or merely toothed. 
Stems branched, leafy, usually bear- 
ing several heads. ° 
Pubescence long and dense; 
rays blue, pink or white... ~~ - 4. E. hispidissimus. 
Pubescence very short. 
Leaves linear-lanceolate, 3- 
nerved ........-.------- 6. E. corymbosus. 
Leaves filiform or linear, 1- 
nerved .......-.------- 11. EF. linearis 
Stems simple, scapiform; head al- 
ways solitary. 
Leaves dentate, broadly spatu- 
late. 
Involucre glandular; stems 
not producing offsets. ... 13. EF. leibergit. 
Involucre glabrate; stems 
= 
producing rosulate offsets. 15. FE. oreganus. 
Leaves entire; involucre not 
glandular. 
Rays white, leaves linear- 
lanceolate... ........--- 8. E. nevadensis. 
Rays violet. 
Involucre very woolly. 14. 2. uniflorus. 
Involucre hispidulous. 7. E. poliospermus., 
Roots annual, fibrous; leaves toothed or lobed. 
Stems diffusely branched; rays pink 100 to 120... 17. E. divergens. 
Stems erect, branched above; rays white 40 to60_.. 18. #. ramosus. 
Rays very short or wanting. 
= 
es 
Plants low; root stout, perennial; heads solitary to 
numerous. 
Leaves ternately cleft or parted; involucre hirsute. 9b. EF. compositus discoideus. 
Leaves linear or linear-spatulate, narrow; invo- 
luere villous ......--..--------------------- 20. E. bloomeri. 
Plants tall; heads several to numerous. 
Rays wanting; heads cymose; leaves firm; root pe- 
rennial .........------------------------ ee 19. FE. eradiatus. 
Rays present, short. 
= 
Heads paniculate; involucre glabrous; root an- 
nual .......2....-2-----2--------------- 21. E£. canadensis. 
Heads corymbose; involucre hirsute at least 
at base; roots biennial. 
Tall, 30 to 60 cm.; heads many....-.-- - 22. FE. acris. 
Low 10 to 20 cm.; heads few........--. 22a. EF. acris debilis 
= 
