70 POLYGONACEAE 



Involucres glabrate: leaves usually less tomentose above. 



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

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



Involucres not strongly angled; those of the forks peduncled. 



62. E. campanulatum. 

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

 margins. „ . . 



Involucres in the forks peduncled. 63. E. brevicaule. 



Involucres all sessile. 64. E. micranthum. 



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



65. E. contorlum. 

 Perianth white or rose-colored. 



Suflruticose 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. spathuHforme. 

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



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



68. E. Ostlundi. 

 Leaf-blades narrowly oblauceolate to linear. . 



Involucres all sessile. 



Leaves mostly flat; involucres narrowly turbinate; perianth 2-2.5 



Tnm long. 69. E. lonchophuUum. 



Leaves mostly revolute; involucres campanulate; perianth 3-3.5 

 mm. long. 70. E. nudicaule. 



Involucres in the forks of the inflorescence, at least the lower, 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 linear-oblanceolate or linear, usually 



revolute. 73. E. tristichum. 



Leaf-blades spatulate to oblauceolate, 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 compoimd, copioiisly branched: intemodes 

 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 slightly floccose. 



81. E. microthecum. 

 Involucres all sessile; pedxmcles densely white-tomentose. 



82. E. nebraskense. 

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



Peduncles not thickened upwards. 



Leaves glabrous or loosely floccose above. 



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

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



84. E. Mearnsii. 

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



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



Branches of the inflorescence strongly angled and deeply grooved. 



87. E. sulcatum. 

 XIV. Annua. 

 One species. 88. E. annuum. 



XV. Racemosa. 

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

 base or subcordate. 89. E. racemosum. 



