BUCKWHEAT FAMILY 69 



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



pink margin. 31. E. Shockleyi. 



L/Obes of the involucres triangular, not scarious-margined. 



32. E. pulvinatum. 

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



33. E. acaule. 

 VIII. Heterose|\ala. 



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



Heads solitary. 



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



Involucres 4^5 mm. long. 



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



36. E. ovalifolium. 

 Perianth cream-colored, ochroleucous, 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. B. chrysops. 



Perianth ochroleucous, 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. i 



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. B. medium. 

 Perianth white 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. 



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



49. E. muUiceps. 

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



X. eLata. 

 One species. 51. E. elatum. 



XI. Fascicitlata. 



One species. 52. E. polifolium. 



XII. Dichotoma. 



Stem leafy, suffrutescent; 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 ascendmg-spreadmg. 



54. E. dichotomum. 

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

 erect, 55. E. lachnostegium. 



Inflorescence glabrous. 56. E. strictum. 



XIII. Cobtmbosa. 

 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 elUptic, oval, or broadly spatulate; involucres glabrous. 



57. E. aureum. 

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

 Undershrubs, leafy only at the base; inflorescence longer than the steni. 

 Involucres vUlous-tomentose; leaf-blades equally white on both sides. 

 Leaf-blades narrowly oblanceolate; branches of the inflorescence strongly 



ascending 59- ^- orendense. 



Leaf-blades broadly spatulate; branches of the inflorescejice more 

 spreading. 60. E. lagopuS. 



