CYPERACEAE 59 



XXXV. MULTIFI<ORAE. 

 Leaf-blades mostly less than 2 mm, wide. 99. C. ieretiuscvla. 



Leaf -blades mostly over 2 mm. wide. 

 Scales acuminate, cuspidate or awned. 

 Perigynia 3-5 mm. long. 100. C. alopecoidea. 



Perig^nia 2-3 mm. long. 

 Leaves as long as the stem or longer : perigynia dull yellow to brown. 



loi. C vulpinoidea. 

 Leaves shorter than the stem : perigynia bright yellow. 



102. C. xanthocarpa. 

 Scales blunt, scarious-tipped. 103. C. Sartwellii. 



XXXVI. MUHLENBERGIANAE. 

 Spikes 1-5-flowered, the lower at least much separated : perigynia nearly terete, 



ellipsoid. 104. C. leiiella. 



Spikes several-many-flowered : perigynia flattened, lanceolate, ovate or 

 roundish. 

 Spikes separated or the upper approximate : perigynia mostly radiating or 

 reflexed. 

 Leaf-blades 1-3 mm. wide. 

 Beak of the perigynium J^-J^ as long as the body : native species of 

 woodlands. 

 Perigynia stellatelyradiating or ascending. 105. C. rosea. 

 Perigynia reflexed, at least when mature. 106. C. retroflexa. 

 Beak of the perigynium more than % as long as the body : introduced 

 species of fields. 107. C. muricaia. 



Leaf-blades 5-9 mm. wide. 108. C. sparganioides. 



Spikes all aggregated or the lower separated : perigynia spreading or as- 

 cending. 

 Leaf-blades relatively thin and lax, 4-8 mm. wide. 109. C. cephaloidea. 

 Leaf-blades relatively stiff, 1-4 mm. wide. 

 Perigynia 2 mm. long or shorter, nerveless or faintly few-nerved. 



no. C. cephalophora. 

 Perigynia 3 mm. long, strongly nerved or nerveless. 



111. C. Muhlenbergii. 



XXXVII. ELONGATAE. 

 Perigynia radiately spreading or reflexed when mature. 

 Perigynium distinctly nerved on both faces : beak rough. 

 Perigynium lanceolate : beak more than K as long as the body. 



112. C sterilis, 

 Perigynium ovate : beak about % as long as the body, abrupt. 



113. C. Atlantica. 

 Perigynium faintly nerved only on the outer face ; beak smoothish. 



114. C. interior. 

 Perigynium appressed or ascending, at least not radiating. 



a. Perigynia ovate, oval, oblong or elliptic. 

 Bracts short, scale-like or obsolete, or the lowest one sometimes surpassing 

 its spike. 

 Spikes silvery green or almost white. 115. C. canescens. 



Spikes brown or brownish. Ii6. C. brunnescens . 



Bracts bristle-form, elongated, much surpassing the 2-4 perigynia. 



117. C. trisperma. 



