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 TOIKV'^. 



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COULTER AND ROSE — NORTH AMERICAN T^MHELLIFERAE. 43 



I.KAVKS not p'lnillcl-voinoil, variable in form and texture. 

 I'asai. i,i;\vi:s imt at all s|>iii\-t(iullic(i. 

 I'iantH low aiKJ siemier, iimstly pmstrato, with small thin leaves. 



I'ractlets leii;;(^i' tiian llu\\cr.<; I'niit strdiiyfly tiiliereiilate 4. E. bnfrhrhiti. 



Kractiots shorter than lli)\\er.^; fruit not strongly tuhercu- 



late 5. E. pniHlvatatn. 



I'lants erect and mostly tall; leaves lliiek; eastern {{i\cii\>i E. ptiyleumae). 

 Leaves elongated, the jietioles long and tistulous. 

 Bractlets entiri!, 

 Heads oblong, with a tiirminal tuft of conspicuous bractlets. 



6. E. jilnilriimrte. 

 Heads globose, without consjiieuous terminal bractlets. . 7. E. Jloridaiinin. 

 Bractlets 3-toothed. 



liraetlets with une(|nid teeth (middle one largest) 8. E. aqualicum. 



Bractlets with equal teeth. 



Slender, 4.5 to 9 dm. high 9. E, ravcni'lll. 



Stout and taller (12 to IS dm.) 10. E. mettnnm. 



TiCaves small, with short petiol<'s. 



Upper leaves simple; bractlets tricuspidate 11 . 7v. inlegrifoUnm. 



Upper leaves i)almately parted; bractlets entire 12. E. hookeri. 



I'asai, i,eaves spiny-toothed (soim^tiines reduced to nodose petioles). 

 Siutheru and soutlnvestern species. 

 Heads small (12 mm. or less); sepals entire. 



Bractlets ."i-toothed 1."?. E. arnmaiicum. 



Bractlets entire. 

 Stems low and diffusely branching; bracts l(!ss conspicuous, green within. 



14. E. diffuHiim. 

 Stem erect, less branching; bracts very conspicuous, not green within. 

 Bracts linear-lancuolate; lower leaves pectinate-dentate or with trian- 

 gular bristly teeth 15. E. wrii/lilii. 



Bracts broadly cuneate; lower leaves not pectinate-dentate. 



Iti. E. Iciinnoni. 

 Heads large (25 to 35 nun. long); sepalsS to5-cuspidate.. 17. E. leavenwurihii. 

 Pacidc slope species. 

 Styles shorter than sepals. 



Bracts and bractlets entire IS. E. nrmalum. 



Bracts and bractlets not eiilire. 



BiactU'ts little longer than the usually bhu' heads 19. /•-'. urticulalum. 



Bractlets twice as long as the heads, which are never 



blue 20. E. petiolalum. 



Styles longer than .stjials. 

 Bractlets but little longer than flowers. 



Bracts weak and reflcxed 21 . E. elongatum. 



Bracts rigid and not reflexcd. 



Ihacts much longer than the Ih^kIs 22. E. jepsoni. 



Bracts little, if at all, longer than the luads. 



1 leads small (about 6 mm. ) 23. E. minimum. 



Heads larger (9 to 10 mm. ) 24. E. nllsmacfoUum. 



Bractlets much longer than the flowers. 



Bracts narrowly lanceolate and si)reading, entire 25. E. longisiylum. 



I'racts very luu-row and rigid, more or less spinose-bristly. 

 Bra(;ts with cons]ucuous scarious margin at base. 



Erect and tall; bracts 18 to 20 mm. long 2(1. /•.'. ohhmceolatum. 



Prostrate; bracts about 10 mm. long 27. E. aristulatum. 



