2 AMERICAN MIDLAND NATURALIST 



d. Denies utrimque 4-5, ampli, atte- 



nuato-acuti 10. E. oxyodontus . 



d. Dentes pauciores, dispersi, parvi. 

 e. Caules pilis diflfusis vel retrorsis 



vestiti 1 1. E. oligodonius . 



e. Caules pilis mollibus longitudinis 

 inaeqtialis repandis et appressis 

 tenuiter vestiti. . .12. E. oligodontus var. acuminatus. 

 A. Flores radiati 6-8 mm. longi, lati, folia 3- 



nervata i-^. E. siihcostatus . 



A. Flores radiati 8-12 mm. longi, lati. 



a. Folia inferiora denticulata 14. E. procerus. 



a. Folia omnia Integra i5- E. anodonius 



Analytical key. 



A. Rays 6-8 mm. long, narrow, 

 a. Leaves entire. 



b. Stem hirsutely scabrous i. E. 



b. Stem scantily covered with soft hairs of 

 unequal length, turned upwards and ap- 



pressed 8. E. asper var 



a. At least some of the leaves dentate. 



c. Lower leaves generally short and broad.. 9. E. 

 c. Lower leaves spatulate-lanceolate .... 2 E. 

 c. Lower leaves long and narrow, slenderly 

 pointed, 

 d. Teeth 4-5 on each side, large, atten- 

 uate pointed 10. E. 



d. Teeth fewer, scattered, small. 



e. Stem covered with spreading or 



retrorse hairs 11. E. 



e. Stem scantily covered with soft 

 hairs of unequal length, turned up- 

 wards and appressed 



\2. E. oligodontus var. 

 A. Rays 6-8 mm. long, broad, leaves 3-nerved . .13. E. 

 A. Rays 8-12 mm. long, broad. 



a. Lower leaves denticulate 14. 



a. All the leaves entire 15. E 



asper Nutt. 



. appressus. 



ahruptorum 

 mu ticolor 



oxyodontus. 



oligodontus. 



acuminatus. 

 subcostatus. 



E. procerus. 

 . anodontus. 



