116 CYPERACEAE 



Beak of the perigynia smooth or very nearly so; scales obtuse to acutish, 

 strongly tinged with reddish brown or chestnut; spikes closely ap- 

 proximate. 

 Terminal spike strongly tapering at base; culms rough at apex only. 



62. C. Lachenalii. 

 Terminal spike little tapering at the base; culms usually very rough. 



63. C. Heleonastes. 

 Beak of the perigynia serrulate, or if smooth scales acutish to cuspidate and 



scarcely, if at all, tinged with reddish brown ; lower spikes remote. 

 Plant glaucous; leaf-blades 2-4 mm. wide; spikes many-flowered; 

 perigynia scarcely beaked, appressed ascending, with emarginate or 

 entire orifice. 64. C. canescens. 



Plant not glaucous; leaf-blades 1-2.5 mm. wide; spikes fewer-flowered; 

 perigynia distinctly beaked, loosely spreading, with minutely biden- 

 tate orifice. 65. C. brunnescens. 



Perigynia ovate, broadest near the base; beak conspicuous, strongly serrulate. 



66. C. arcta. 



18. PHYLLOSTACHYAE. 



Perigynia with long smooth beak; foliage deep green. 67. C. durifolia. 



Perigynia with short sparingly serrulate beak; foliage light or glaucous green. 



68. C. saximontana. 



19. POLYTRICHOIDEAE. 



Represented by one species. 69. C. leptalea. 



20. OBTUSATAE. 

 Represented by one species. 70. C. obtusala. 



21. NlTIDAE. 



Represented by one species in our range. 71. C. supina. 



22. RUPESTRES. 



Represented by one species. 72. C. rupestris. 



23. FlRMICULMES. 



Represented by one species in our range. 73. C. Geyeri. 



24. FILIFOLIAE. 



Leaf-blades filiform at base, 0.25-0.5 mm. wide; culms filiform, obtusely triangular, 



smoothish; lowest scale rarely awned. 

 Perigynia sharply triangular below, obpyramidal; basal sheaths rarely filamentose. 



74. C. clynoides. 

 Perigynia rounded on the angles, obovoid to globose; basal sheaths filamentose. 



75. C. filifolia. 



Leaf- blades flattened at base, 1.5-2 mm. wide; culms stoutish, sharply triangular, often 

 much roughened; lowest scale conspicuously awned. 76. C. oreocharis. 



25. SCIRPINAE. 



Culms phyllopodic, the culm-leaves 6-10; scales concealing perigynia. 



77. C. pseudoscirpoidea. 

 Culms aphyllopodic, the culm-leaves 3-6; scales shorter than perigynia. 



Perigynia lanceolate, flattish, 4 mm. long. 78. C. slenochlaena. 



Perigynia broader, triangular, 3 mm. long or less. 



Scales very minutely hyaline-margined; perigynia whitish-pubescent. 



79. C. scirpoidea. 

 Scales very broadly hyaline-margined; perigynia yellowish-hirsute. 



80. C. scirpifonnis. 

 26. MONTANAE. 



Basal spikes absent. 



Long stoloniferous ; scales about equalling the perigynia. 81. C. heliophila. 

 Without long stolons; scales much shorter than the perigynia. 



82. C. Peckii. 

 Basal spikes present. 



Lower bract exceeded by the culm, scale-like, hyaline-margined at base. 



83. C. umbcllatn. 

 Lower bract normally exceeding the culm, leaf-like, not hyaline-margined at base. 



Perigynia 2.75 mm. long or less, shallowly bidentate; rootstocks slender. 



84. C. dejiexa. 

 Perigynia longer, deeply bidentate; culms densely cespitose. 



85. C. Rossii. 

 27. DlGITATAE. 



Basal spikes present; scales abruptly cuspidate. 86. C. pedunculata. 



Basal spikes absent; scales not abruptly cuspidate. 



Staminate spike 3-6 mm. long; scales obtuse, one-half as long as the perigynia. 



87. C. concinna. 

 Staminate spike 8-22 mm. long; scales acute to acuminate, from little shorter than 



to exceeding the perigynia. 

 Perigynia loosely pubescent, wider and longer than the scales; Staminate spike 



nearly sessile; pistillate spikes few-flowered. 88. C. concinnoides. 



Perigynia appressed-pubescent, narrower and shorter than the scales; Staminate 

 spike noticeably peduncled; pistillate spikes many-flowered. 



89. C. Richardsonii. 



