CYPERACEAE 



I8.S 



C. lacustris. 

 C. Walteriana. 



37. Hirtae. 

 Staminatc scales not ciliate. 



Perigynia beak much shorter than the body, the teeth 

 I mm. long or less. 

 Perigynia glabrous to sparsely pubescent. 



Leaves 6-12 mm. wide, flat. 124. 



Leaves 2-4 mm. wide, becoming involute. 125. 



Perigynia densely or strongly pubescent. 



Perigynia beak with hyaline orifice at length 

 somewhat bidentate; staminate spike usuallj 

 one. 126. C. vestita. 



Perigynia beak with non-hyaline, strongly biden- 

 tate orifice; staminate spikes more than one. 

 Leaves flat, more than 2 mm. wide. 

 Leaves involute, 2 mm. wide or less. 

 Perigynia beak, including teeth, nearly as long as body, 

 the teeth 1.7 mm. long or more. 

 Staminate scales strongly ciliate. 



38. Flavae. 

 Leaves involute; perigynia ascending, not yellowish. 

 Leaves not involute; perigynia squarrose, yellowish. 



Perigynia 2-3 mm. long, the beak scarcely half the 



length of the body. 

 Perigynia 4-6 mm. long, the beak about the length of 

 the body. 

 Scales hidden; perigynia 4 mm. long. 

 Scales conspicuous; perigynia 5-6 mm. long. 



39. Collinsiae, represented only by 



40. Folliculatae, represented only by 



41. Physocarpae. 

 Pistillate scales, except rarely the lowest, not rough awncd. 



Pistillate spikes oblong to cylindric, 15-many-flowered. 

 Perigynia not reflexed; bracts not more than several 

 times exceeding spikes. 

 Achenes not excavated on one side or but little si>. 

 Beak of perigynia smooth. 



Culms sharply triangular, rough above, 



scarcely spongy at base. 

 Culms obtusely triangular, usually smooth 

 above, often thick and spongy at base. 

 Beak of perigynia rough. 

 Achenes deeply excavated on one side. 

 Lower perigynia reflexed; bracts many times ex- 

 ceeding spikes. 

 Pistillate spikes globose or short oblong, 5-15-flowered. 

 Pistillate scales rough-awned. 



Spikes cylindric, 14-19 mm. thick. 

 Spikes narrow cylindric, 8-12 mm. thick. 



42. Pseudo-Cypereae. 

 Perigynia suborbicular in cross section, more or less inflated. 



Spikes linear-cylindric; staminate scales scarcely awned. 145. 



127. 



128. 



129. 

 130. 



131- 



■32- 



133- 

 '34- 

 135- 

 136. 



C. lanuginosa. 



C. lasiocarpa. 



C. Iruhocarpa. 

 C. hi rlu. 



C. extensa. 



C. Oederi. 



C. cryplolepis. 

 C. flava. 

 C. Coliinsii. 

 C. foil kit lata. 



