BUCKWHEAT FAMILY 213 



Leaf-blades elliptic or oval, not strongly revolute; scape 1-3 cm. long. 



Perianth yellow; lobes of the involucres lanceolate, more than twice as long as the 



tube. 30. E. longilobum. 



Perianth white or pinkish; lobes of the involucres not twice as long as the tube. 

 Lobes of the involucres oblong or ovate, with a more or less scarious white or 



pink margin. 31. E. Shockleyi. 



Lobes of the involucres triangular, not scarious-margined. 



32. E. pulvinalum. 

 Leaf-blades linear-oblong, strongly revolute; scape none or very short. 



33. E. acaule. 

 VIII. Heterosej'.ala. 



Heads several, cymose-proliferous, the central head sessile. 34. E. proliferum. 



Heads solitary. 



Involucres about 7 mm. long; leaf-blades oval. 35. E. orthocaulon. 



Involucres 4-5 mm. long. 



Perianth bright yellow or in age purplish; leaf-blades about as broad as long. 



36. E. ovalifolium. 

 Perianth cream-colored, ocliroleucous, or isabel-colored. 



Perianth 2.5-3.5 mm. long; leaf-blades rounded-oval or ovate. 



37. E. depressum. 

 Perianth 4-5 mm. long; leaf-blades elliptic, oblong, or spatulate. 



38. E. ochroleucum. 

 IX. Capitata. 



Perianth yellow. 



Bracts and involucres membranous; the former broadly lanceolate; the lobes of the 

 latter ovate or triangular; densely pulvinate-cespitose perennials. 

 Perianth bright yellow. 39. E. chrysops. 



Perianth ocliroleucous, sometimes tinged with rose. 40. E. Kingii. 



Bracts and involucres firm; the former subulate or narrowly lanceolate (except in 

 E. medium); the lobes of the latter lanceolate; perennials with a cespitose 

 woody caudex. 

 Perianth ochroleucous. 41. E. loganum. 



Perianth golden yellow. 



Leaf-blades oblanceolate or oblong, tomentose on both sides. 



42. E. chrysocephalum. 

 Leaf-blades Linear or narrowly linear-oblanceolate, in age greener above. 



43. E. medium. 

 Perianth wliite or rose-colored. 



Perianth glabrous; perennials with a cespitose woody caudex. 



Lobes of the involucres lanceolate, acute, not scarious-margined. 



Heads about 1 cm. broad; perianth fully 3 mm. long; leaf-blades 3-8 cm. long. 



44. E. Brandegei. 

 Heads about 0.5 cm. broad; perianth about 2 mm. long; leaf-blades 1-2 cm. 



long. 45. E. depauperatum. 



Lobes of the involucres oval to orbicular, scarious-margined. 



Leaves glabrate above; perianth 3-5 mm. long; involucres in small heads. 

 Lobes of the involucres much shorter than the tube. 



46. E. coloradense. 

 Lobes of the involucres about as long as the tube. 



47. E. pauciflorum. 

 Leaves white-tomentose on both sides; perianth 2.5 mm. long; involucres 



solitary. 48. E. mancum. 



Perianth pubescent. 



Suffruticose leafy-stemmed perennial, with decumbent branches, villous. 



49. E. multiceps. 

 Pulvinate perennial, acaulescent, silky-hirsute. 50. E. villiflorum. 



X. El.\ta. 

 One species. 51. E. datum. 



XI. Fasciculata. 



One species. 52. E. polifolium. 



XII. DiCHOTOMA. 



Stem leafy, suff rutescent ; outer perianth-segments suborbicular. 



53. E. niveum. 

 Stem scapiform, with a cespitose woody caudex; outer perianth-segments oval. 

 Inflorescence more or less floccose. 



Involucres 5-6 mm. long; branches of the inflorescence ascending-spreading. 



54. E. dicholomum. 

 Involucres 3-4 mm. long; branches of the inflorescence strongly ascending, almost 

 erect. 55. E. lachnostegium. 



Inflorescence glabrous. 56. E. slriclum. 



XIII. CORYMBOSA. 



Branches of the inflorescence not grooved. 

 Perianth yellow. 



Plants more than 2 dm. high; leaves not heath-like. 

 Leafy shrubs; inflorescence shorter than the stem. 



Leaf-blades elliptic, oval, or broadly spatulate; involucres glabrous. 



57. E. aureum. 

 Leaf-blades oblanceolate; involucres tomentose. 58. E. idahoense. 



