CYPERACEAE. 67 



Spike dull-brown ; perigynium erect or slightly spreading at maturity, obovate, 

 shortly beaked or beakless, the orifice entire. 54. C. rupestris. 



Spike shining, reddish-brown ; perigynium horizontally bent at maturity, turgid, 

 coriaceous, obscurely nerved, the short beak with hyaline orifice. 



55. C. obtusata. 



20. Elynanthae. 



Spike single, androgynous, the pistillate portion few-flowered; scales very 

 broad; perigynium membranaceous, whitish to brown, erect, sessile, oval to 

 obovoid, pubescent or ciliate above, the beak short, with the orifice entire or 

 obliquely cut; stigmata 3. 



Spike silvery-shining, light-brown ; perigynium oval, pubescent, the beak entire. 



56. C. filifolia. 

 Spike reddish-brown ; perigynium obovoid, attenuated at both ends, the beak cili- 

 ate, obliquely cut. 57. C. elynoides. 



21. Sphaeridiophorae. 



Spike one, the plant dioecious or monoecious, or several, the terminal 

 staminate, the lateral pistillate; the latter few-flowered, roundish, mostly ses- 

 sile or the basal long-peduncled ; bracts fohaceous, sheathless; scales acu- 

 minate, often mucronate, green to blackish ; perigynium dark-green, stipitate 

 or sessile, obovate to globose, pubescent, obscurely nerved, the beak mostly 

 short, obliquely cut or bidentate, with the teeth erect; stigmata 3. 



Spikes solitary ; beak short, obliquely cut. 



Dioecious ; spike very dark, many-flowered ; perigynium strigosely hairy, obo- 

 vate to oval. 58. C. scirpoidea. 

 Monoecious ; spike androgynous, silvery-shining ; perigynium minutely pubescent, 

 broadly elliptic. 59- C. oreocharis. 

 Spikes several. 



Rhizome stoloniferous ; spikes dark-colored, sessile or nearly so ; perigynium 

 globose, abruptly beaked ; beak short, entire or 2-lobed. 60. C. pennsylvanica. 

 Rhizome caespitose ; spikes peduncled, light-green to brown. 



Perigynium oval, stipitate; beak bifid. 61. C. Rossii. 



Perigynium globose ; beak long, obliquely cut. 62. C. umbellata. 



• 

 22. TrICHOCARPAE. 



Spikes several, cylindrical, dense-flowered, sessile or the lowest one pedun- 

 cled, but erect, remote, the terminal and uppermost lateral staminate, the 

 others pistillate; bracts foliaceous, long and sheathing; scales purplish or 

 brown, mucronate to aristate; perigynia erect, sessile, ovate to ovate-lanceo- 

 late, turgid, more or less pubescent, nerved, the beak prominent, bidentate; 

 stigmata 3. 



Perigynium ovate, densely pubescent. 63. C. lanuginosa. 



Perigynium ovate-lanceolate, sparingly pubescent, the beak with very long, diverg- 

 ing teeth. 64- C. aristata. 



23. Hymenochlaenae. 



spikes several, androgynous or the terminal staminate, the lateral pistil- 

 late, not very dense-flowered, long-peduncled and drooping; bracts folia- 

 ceous, sheathing; scales hyaline, mucronate; perigynia erect to slightly 



