288 CYPERACEAE. 



% J Pistillate spikes drooping or spreading (erect or little spreading in no. 78). GRACILLIMAE. 

 Perigynia i"-2" long, slightly swollen; spikes linear or linear-cylindric. 



Plant glabrous; perigynia obtuse. 77. C. gracillima. 



Sheaths pubescent; perigynia pointed at both ends. 



Perigynia i" long; spikes erect or somewhat spreading. 78. C. aestiralis. 



Perigynia 2" long; spikes drooping, at least when old. 79. C. oxylepis. 



Perigynia 2" '-z%" long, manifestly swollen; spikes oblong or oblong-cylindric. 



Perigynia faintly few-nerved; scales ovate, acute or short-awned. 80. C. formosa. 



Perigynia strongly many-nerved ; scales lanceolate, long-awned. 81. C. Daz'isii. 



| f Terminal spike entirely staminate, or sometimes pistillate at the base. Nos. 82-92. ( See no. 14 



Perigynia manifestly beaked, nerved or nerveless; pistillate spikes drooping, at least when old. 

 Beak of the pengynium cylindric or subulate, 1-2 times as long as the body. SYLVATICAE. 

 Perigynia broadly oval, smooth, spreading. 82. C. longirostris. 



Perigynia narrowly conic, tuberculate-hispid, appressed. 83. C. Assiniboinensis. 



Beak of the perigynium not more than one-half as long as the body. 



Leaves pubescent. FLEXILES. 84. C. castanea. 



Leaves glabrous. 



Pistillate spikes narrowly oblong, 2"-6" long; perigynium i" long; arctic and alpine 



species. CAPILLARES. 85. C. capillaris. 



Pistillate spikes linear, i'~3' long; perigynium 2" -3" long. DEBILES. 

 Perigynia membranous, few-nerved; pistillate spikes slender. 



Leaves 2 1 A"~5" wide; scales two-thirds as long as the perigynia. 



86. C. arc tat a. 

 Leaves i"-2 l A" wide; scales one-half as long as the perigynia. 



87. C. tennis. 

 Perigynia coriaceous, strongly many-nerved; pistillate spikes thicker. 



88. C. oblita. 

 Perigynia beakless or minutely beaked, finely many-striate ; spikes erect or nearly so. GRISEAK. 



Leaves slightly or not at all glaucous. 



Perigynia little longer or shorter than the scales. 



Pistillate spikes dense, usually many-flowered; leaves 2" -3" wide, spreading, soft. 



89. C. grisea. 

 Pistillate spikes loosely several-flowered; leaves i"-2" wide, mostly erect and rigid. 



90. C. amphibola. 

 Perigynia 2-3 times longer than the scales. 91. C.flaccosperma. 



Plant very glaucous all over. 92. C. glaucodca. 



2. Pistillate spikes small, few-many-flowered, mostly 3" -12" long (sometimes longer in nos. 103* 

 104, 116). Nos. 93-132. (See also nos. 44, 48, 53-55, 61, 63-65, 68, 73, 75, 80, 84, 85 and 89-92.) 



* Perigynia glabrous. Nos. 93-120. (See no. 123.) 

 t Pistillate spikes many-flowered, X'-i' long, usually dense. Nos. 93-99. 



Pistillate spikes scattered, distant, long-stalked or the 2 upper ones close together and nearl}- ses- 

 sile. GRAXULARES. 

 Bracts elongated, mostly overtopping the spikes; perigynia strongly many-nerved. 



93. C. graniilaris. 



Bracts short, rarely overtopping the spikes; perigynia obscurely few-nerved. 94. C. Crawei. 

 Pistillate spikes close together and nearly sessile at the summit of the culm, or the lowest distant 



and stalked. 

 Beak of the perigynium stout, 2-toothed; plants glabrous. EXTENSAE. 



Leaves strongly involute; perigynia brown, the beak shorter than the body. 



95. C. extensa. 

 Leaves flat, i"-2*A" wide; perigynia yellow when mature, 2" -3" long, the beak about a& 



long as the body. 96. C. flava. 



Leaves flat, i" wide or less; perigynia dark green, i" long, the beak one-half as long as the 



body. 97. C. I'iridnla. 



Beak of the perigynium short, entire or none; leaves, or their sheaths, more or less pubescent 

 PALLESCENTES. 



Perigynia faintly few-nerved, beakless. 98. C. pallescens. 



Perigynia strongly many-nerved, cylindric-beaked. 99. C. abbrci'iata. 



tt Pistillate spikes few-several-flowered, often loose. Nos. 100-120; 136-138. 

 J Scales of the spike normal, not elongated and leaf-like. Nos. 100-120. 

 'i Leaves i"-i8" wide; bracts leafy, usually large. Nos. 100-119. 

 O Perigynia green (yellow or purple in no. 116). Nos. 100-117. 



Perigynia finely many-striate. OLIGOCARPAE. 

 Sheaths glabrous. 



Perigynia narrowed at both ends, beakless. 100. C. conoidt-a. 



IVrigynia with a short entire beak. 101. C. oligocarpa. 



Slu atlis pubescent. 102. C. Hitchcockiana. 



Perunmia with fi-w or many, mostly strong nerves. LAXIFLORAE. 

 I'lants not at all glaucous, or very slightly so. 

 Beak^of the perigynium straight, slender. 



Culms slender, spreading; pistillate spikes 2 or 3, stalked, spreading. 



103. C. altocaulis. 



Culms stout, erect; pistillate spikes i or 2, erect. 104. C. polvmorplia. 



Beak of the perigynium bent, short or none. 



Leaves mostly narrow, i"-6" wide. . 



Scales, at least the upper, obtuse. 



Bracts elongated ; spikes loosely flowered; culms slender. 105. C. tetanica. 

 Bracts short; spikes densely flowered; culms stout. 106. C. Meadii. 



