116 CYPERACEAE 



Beak of the perigjTiia smooth or very nearly so; soajes 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. Heleonasles. 

 Beak of the perig\niia 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. cnnescens. 



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. 



Perigj'nia ovate, broadest near the base; beak conspicuous, strongly serrulate. 



66. C. arcta. 



IS. PlIYLLOSTACHYAE. 



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



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



68. C. saiimonlana. 



19. POLYTRICHOIDE.\E. 



Represented by one species. 69. C. leptalea. 



20. Obtusatae. 

 Represented by one species. 70. C. oblusala. 



21. NiTIDAE. 



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



22. RUPESTRES. 

 Represented by one species. 72. C. rupestris. 



23. PiRMICULMES. 



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, 

 sraoothish; lowest scale rarely awned. 

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



74. C. clynoides. 

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



75. C. fllifolia. 

 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. pseiidoscirpoidea. 

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



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



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



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



79. r. scirpoidea. 

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



80. C. scirpiformis. 



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. Pvckii. 

 Basal spikes present. 



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



83. C. umbclMa. 

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



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



84. C. dciicia. 

 Perigynia longer, deeply bidentate; culms densely cespitose. 



85. C. Rossii. 



27. DiGITATAE. 



Basal spikes present; scales abruptl.v cuspidate. 86. C. pedunculala. 



Basal spikes absent; scales not abruptly cuspidate. 



Stanunate spike 3-6 mm. long; scales obtuso, one-half as long a,s the perigynia. 



87. C. cnncinna. 

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

 to exceeding the perigynia. 

 Perigynia loosely put)cscent, wider and longer than the scales; staminate spike 



nearly sessile; ])isiillatc spikes few-flowered. 88. C concinnoides. 



Perigynia api)re.ssc(l-|)ul>escent, narrower and shorter than the scales; staminate 

 spike noticeal)l.y peduncled; pistillate spikes many-flowered. 



89. C. liichardsonii. 



