242 MISC. PUBLICATION 4 2 3, U. S. DEPT. OF AGRICULTURE 



31. Perianth sericeous externally, yellow; inflorescence relatively short, 

 compact, short-branched; stems and leaves hoary with dense, 

 silky pubescence; involucres rather densely sericeous; achenes 4 to 



5 mm. long, winged above the middle; plant sometimes subscapose, 

 with reduced stem leaves 29. E. hieracifolium. 



31. Perianth glabrous externally; inflorescence elongate, open, long- 

 branched; stems and leaves green, loosely villous or glabrate ; achenes 



6 to 8 mm. long, winged nearly to the base (32). 



32. Achenes 6 to 7 mm. long, usually considerably more than half as 

 wide; involucres rather sparsely sericeous; perianth yellow. 



30. E. ALATUM. 



32. Achenes 7 to 8 mm. long, about half as wide; involucres glabrous or 

 sparsely sericeous; perianth purplish or yellowish. 



31. E. TRISTE. 

 30. Achenes not conspicuously winged (33). 



33. Peduncles filiform or nearly so, 5 to 20 mm. long; stems tall, sparingly 



branched; larger leaves usually orbicular or nearly so and more or 



less cordate; perianth yellow or fading pinkish; involucres glabrous 



externally (34). 



34. Perianth whitish hispidulous externally, the lobes not panduriform; 



one or more internodes of the scapes usually strongly inflated; 



well-developed leaves basal only, rather sparsely villous or hirsute. 



13. E. INFLATUM. 



34. Perianth glabrous or very nearly so externally, the lobes panduriform ; 



scapes not inflated; well-developed leaves at several of the 

 crowded lower nodes of the stems, sparsely lanate to white- 



tomentose on both faces 27. E. capillare. 



33. Peduncles not filiform; larger leaves usually considerably longer than 

 wide, not cordate, except sometimes in E. racemosum and E. 

 jonesii (35). 



35. Perianth attenuate at base, stipitate; bracts subtending the divisions 



of the inflorescence large, verticillate, resembling the basal leaves 

 but somewhat smaller; involucres turbinate, many-flowered, 

 membranous, villous or sericeous externally, not strongly 

 ribbed (36). 

 36. Perianth cream -colored or pinkish, densely silky-villous externally. 



32. E. JAMESII. 

 36. Perianth bright yellow (37). 



37. Stems usually only once-forked and bearing a single whorl of 



foliaceous bracts; inflorescence compact, often subcapitate; 



involucres few (38) . 



38. Involucres short-toothed or subtruncate; perianth densely 



silky-villous externally 33. E. flavum. 



38. Involucres deeply cleft, the lobes usually reflexed; perianth 



glabrous externally 34. E. umbellatum. 



37. Stems more than once-forked and bearing more than one whorl 

 of foliaceous bracts; inflorescence more open, never sub- 

 capitate (39). 



39. Involucres dentate with broad, erect or somewhat revolute 



teeth; perianth silky-villous externally. 



35. E. ARCUATUM. 

 39. Involucres deeply cleft, usually to the middle or farther, the 



lobes more or less reflexed; perianth glabrous externally. 



36. E. COGNATUM. 

 35. Perianth not attenuate-stipitate; bracts subtending the divisions of 



the inflorescence much smaller than the basal leaves and usually 

 inconspicuous, but occasionally large and foliaceous in E. 

 racemosum (40). 

 40. Plant pulvinate-cespitose, very pubescent; involucres few, villous 

 or tomentose externally; scapes leafless except near the apex 

 (41). 

 41. Scapes not more than 8 cm. long; perianth villous outside, 

 white or pink (42) . 

 42. Leaf blades villous-sericeous, elliptic or lanceolate, acute. 



39. E. VILLIFLORUM. 





