70 POLYGONACEAE 



Involucres glabrate; leaves usually less toraentose above. 



Leaf-blades oblanceolate or broadly oblong, not strongly revolute. 

 Involucres strongly angled, all sessile. 61. E. Thompsonae. 



Involucres not strongly angled; those of the forks pedimcled. 



62. E. campanulatum. 

 Leaf-blades linear or narrowly Unear-oblanceolate, usually with revolute 

 margins. 

 Involucres in the forks peduncled. 6.3. E. brevicaule. 



Involucres all sessile. 64. E. micranthum. 



Plants depressed, less than 1 dm. high, with heath-Uke leaves. 



65. E. contortum. 

 Perianth white or rose-colored. 



Suffruticose plants, leafy only at the base; inflorescence longer than the stem. 

 Involucres tomentose, all sessile. 66. E. spathulatum. 



Involucres glabrous, at least in age. 

 Leaf-blades spatulate or elliptic. 



Pedicels of the lower forks scarcely longer than the involucres; lobes 

 of the latter as broad as long; perianth 3 mm. long. 



67. E. spathuUforme . 

 Pedicels of the lower forks several times as long as the involucres ; lobes 



of the latter longer than broad; perianth 2 mm. long. 



68. E. Ostlundi. 

 Leaf-blades narrowly oblanceolate to linear. 



Involucres all sessile. 



Leaves mostly flat; involucres narrowly turbinate; perianth 2-2.. 5 



mm. long. 69. E. lonchophyllum. 



Leaves mostly revolute; involucres campanulate; perianth 3-3.5 

 mm. long. 70. E. nudicaule. 



Involucres in the forks of the inflorescence, at least the l,ower, distinctly 

 peduncled. 

 Involucres broadly campanulate, about as wide as long. 



71. E. scoparium. 

 Involucres turbinate, decidedly longer than broad. 



Branches of the inflorescence almost erect. 



72. E. grangerense. 

 Branches of the inflorescence ascending-spreading. 



Leaf-blades narrowly Unear-oblanceolate or linear, usually 



revolute. 73. E. trislichum. 



Leaf-blades spatiilate to oblanceolate, flat. 



74. E. salicinum. 

 Shrubby plants, with the leafy stem usually longer than the inflorescence. 

 Leaves not revolute or scarcely so, distinctly petioled. 



Leaf-blades relatively broad, oblong to rounded-oval or obovate, obtuse. 

 Involucres 4-5 mm. long. 75. E. Fendlerianum. 



Involucres 2-3 mm. long. 



Branches of the inflorescence divaricate. 76. E. divergens. 

 Branches of the inflorescence ascending. 



Leaf-blades rounded or subcordate at the base, decidedly crisp. 



77. E. Jonesii. 

 Leaf-blades acutish at the base, not crisp, except sometimes the 

 margins. 

 Inflorescence and stem loosely floccose, in age inclined to 



become glabrate. 78. E. corymbosum. 



Inflorescence and stem permanently and densely white- 

 tomentose. 79. E. salinum. 



Leaf-blades narrow, spatulate to linear, mostly acute at the apex. 



Inflorescence many times compound, copiously branched; internodes 

 long. 

 Inflorescence tomentulose, broom-like, with strongly ascending 



branches; involucresabout 1.5 mm. long. 80. E. effusum. 

 Inflorescence glabrous, lax and with spreading branches; involucres 

 2-2.5 mm. long. 74. E. salicinum. 



Inflorescence less compound; branches and internodes short, mostly 

 spreading. 

 Involucres in the forks peduncled; peduncles sUghtly floccose. 



81. E. micrnthecum. 

 Involucres all sessile; peduncles densely white-tomentose. 



82. E. nebraskense. 

 Leaves linear or Unear-oblanceolate, strongly revolute, subsessile. 



Pedimcles not tliickened upwards. 



Leaves glabrous or loosely floccose above. 



Stem 1—4 dm. high; leaves floccose above. 83. E. Simpsoni. 

 Stem less than 1 dm. liigh; leaves glabrous above. 



84. E. Mcarnsii. 

 Leaves densely villoiis on both sides. 85. E. bicolor. 



Peduncles clavate-thickened upwards. 86. E. clavellatum. 



Branches of the inflorescence strongly angled and deeply grooved. 



87. E. sulcatum. 

 XIV. Annu.\. 

 One species. 88. E. annuum. 



XV. R.\CEMOS.\. 



Leaves crowded on the short branches of the caudex; blades abruptly narrowed at the 

 base or subcordate. 89. E. racemosum. 



