44 



CYPERACEAE. 



C. douglasii. 

 C. camporum. 



C. athrostachya. 



C. hoodii. 



C. pachystachya. 

 C. multimoda. 



C. arcta. 



C. stipata. 

 C. diandra. 



Heads pale, dense, ovoid; pcrigynia lanceolate, the 



smooth beak as long as the body. 

 I leads brown, looser, elongate; perigynia ovate, the 



short beak serrulate. 



V>t dioecious, the staminate flowers either at the top 

 or i lie base of the spikelets; heads very dense. 

 Brad exceeding the head. 

 Brad small or wanting. 



Spikes staminate at top; perigynia dark, nar- 

 rowly margined. 

 Spikes staminate at base; perigynia pale, rather 

 broadly margined. 

 Heads pyramidal-ovate, very dense. 

 Iliads looser, some of the lower spikes 

 separate. 

 Perigynia not margined. 



i ruinate flowers at base of spikelets; head bractless; 



beak of the perigynium serrulate. 



iminate flowers at the top of spikelets; bract 



present ; beak of perigynium not serrulate. 

 Inflorescence dense, oblong or pyramidal; perigynia 



pale, spongy at base, 4-5 mm. long. 

 Inflorescence branched at base, rather loose; peri- 

 gynia brown, not spongy at base, 3 mm. long. 



tion 2. Spikes of two sorts, except when solitary, the lower wholly 

 pistillate, sessile or stalked, the upper one or two slender and wholly staminate, 

 nr sometimes bearing pistillate flowers at base or apex; stigmas 3 and akenes 

 3-angled, or if stigmas 2 and akenes lenticular the lower spikes are stalked. 



Subgenus Eucarex. 

 Spike solitary' and terminal. 



Leaves filiform; bract scale-like. 

 Leaves flat; bract foliaceous. 

 Spiki b several, distinct. 



Stigmas 2; akenes lenticular. 



Perigynia subglobose, almost beakless. 

 Perigynia flattened, short-beaked. 



les acute; perigynia strongly nerved. 

 Scales obtuse; perigynia faintly nerved. 



Perigynia stipitate; scales partly green; sheaths 



green. 

 Perigynia not stipitate; scales wholly purple; 

 sheaths purple, 

 mas 3; akenes 3-angled. 



Bi ik ol perigynium short, entire or merely emarginate. 

 Perigynia pubescent. 

 Scales acuminate. 

 Scales obtuse. 

 P( rigj nia glabrous. 



es broad; spikes 6-10 cm. long. 

 Leaves rather narrow; spikes 1-3 cm. long. 

 k of perigynium rather long, bidentate. 



vnia hairy, firm. 

 Perigynia glabrous. 



Perigynia not inflated, strongly nerved, the 

 teeth 2 mm. long, recurved. 

 Sheaths pubescent; spikes ascending. 

 Sheaths glabrous; spikes nodding. 

 Perigynia inflated, thin. 



C. filifolia. 

 C. geyeri. 



C. aurea. 



C. nebrascensis. 



C. kelloggii. 



C. prionophylla. 



C. rossii. 



C. concinnoides. 



C. amplifolia. 

 C. aperta. 



C. lanuginosa. 



C. atherodes. 

 C. comosa. 



