BUCKWHEAT FAMILY 215 



T>eavos donscly villous on hotli sides. 85. E. bicolor. 



Peduticlo; claNati'-tliiikfiit'il ui)\v;i,rds. 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. 



Leaves scattered on the friiticose branches; blades tapering at the base. 



Leaf-blades elliptic or oblanceolate. 90. E. Wrightii. 



Leaf-blades linear. 91. E. leptocladon. 



XVI. ViRGATA. 



stem neither divaricately branched, nor densely floccose. 



Involucres cylindric; perianth-segments oblong or oval; plant with few branches. 

 Involucres about 3 mm. long. 92. E. vimineum. 



Involucres about 2 mm. long. 93. E. Baileyi. 



Involucres campanulate, 1-1.5 mm. long; perianth-segments cuneate, flabellate, or 

 fiddle-shaped: plants with numerous branches. 

 Branches not inciu*ved in age; leaf-blades ovate or oblong. 



94. E. densum. 

 Branches incurved in age; leaf-blades orbicular or subreniform. 



95. E. nidularium. 

 Stem divaricately branched, densely floccose. 96. E. Plumatella. 



XVII. Pedunculata. 



Perennials with a woody caudex. 97. E. tenellum. 



Annuals. 



Perianth glabrous or in E. T homasi i und E. nutans somewhat pubescent; segments 

 mostlj' obtuse or rounded at the apex. 

 Peduncles not glanflular. 



Scaiic and its branches glabrous. 



Pf'iuncU'd reflcxed or at least divaricate; leaves tomentose on both sides, 

 less so above. 

 Involucres 1.5-2 mm. long; perianth 1.5-2 mm. long. 



Peduncles shorter than the involucres ; outer perianth-lobes ovate or 

 subreniform. 

 Perianth pale yellow; outer segments subreniform. 



98. E. Honkeri. 

 Perianth white; outer segments ovate. 99. E. defleium. 

 Pedimcles longer than the involucres; outer perianth-segments 

 obovate or pandiu-iforra ; perianth white or pinkish. 



100. E. ccrnuum. 

 Involucres 0.5 mm. long; perianth 1-1.5 mm. long, yellowish with red- 

 dish veins. 101. E. Wetherillii. 

 Peduncles erect or ascending. 



Leaves more or less tomentose beneath. 

 Involucres 1.5-2 mm. long. 



Perianth yellow: segments similar. 102. E. pusillum. 



Perianth wliite or rose-colored; segments unlike. 



Involucres campanulate; outer perianth-segments flabellate. 



103. E. rotundifolium. 

 Involucres turbinate; outer perianth-segments not flabellate. 

 Outer perianth-segments ol)long-ovate, the inner ones 



entire. 104. E. insigne. 



Outer perianth-segments subreniform. the inner ones 3- 

 toothed, much smaller. 105. E. lurbinatum. 



Involucres scarcely 1 mm. long; perianth yellowish or white, usually 

 somewhat liispidulous at the base. 106. E. Thomasii. 



Leaves green, glabrate or sparingly pilose. 107. E. Gordonii. 

 Scape more or less pubescent, at least at the nodes. 



Leaves white-lanate beneath. 108. E. subreni forme. 



Leaves green on both sides, sparingly pilose. 109. E. trinervatum. 



Peduncles glandular; leaves tomentose. 



Outer perianth-segments oval, emarginate or retuse, the inner ones oblong. 



110. E. nutans. 



Outer perianth-segments ovate-cordate, the inner ones oblong-ovate, acute. 



111. E. Parryi. 

 Perianth pubescent; segments ovate or lanceolate, acute. 



Peduncles and usually also the scape glandular; leaves green, merely hirsute be- 

 neath. 112. E. glandulosum. 

 Peduncles and scape not glandular. 



Leaves floccose or tomentose beneath. 113. E. Ordii. 



Leaves green, merely pilose or hirsute. 



Accessory branches at the lower forks of the inflorescence many and nearly 

 as strong as the primary ones; all divaricate. 

 Scape slightly if at all inflated. 114. E. trichopodum. 



