CYPERACE^. (SEDGE FAMILY.) 389 



14. Staminate flowers borne at the top of the pistillate spikes ; or in the Are- 

 nance spikes often wholly staminale and the plants occasionally dicecious. 



ACROARRHEN.E, Anderss. 



* Spike one and simple : plants very small. NARDIN^E, Tuckm. 



52. C. nardina, Fries. Densely cespitose : culms to 5 inches high, rigid, 

 about the length of the very numerous, setaceous, rigid or stiffly recurved leaves : 

 spike 1 to 4 lines long, compactly flowered : perigynium oval or elliptic, obscurely 

 nerved, abruptly very short beaked, erect, when mature usually about the length 

 of the broad and obtuse brown scale. Upper Marais Pass ( W. M. Canby), and 

 high northward. Resembles the tristigmatous No. 14, with which it should 

 perhaps be associated. (Eu.) 



53. C. gynocrates, Wormsk. Creeping : culms 3 to 8 inches high, longer 

 than the rigid, erect or spreading leaves : spike 2 to 6 lines long, loosely flow- 

 ered (perigynium sometimes but one, C. monosperma, Macoun) : perigynium 

 ovate, prominently nerved, gradually and conspicuously beaked, spreading at ma- 

 turity, longer than the acute scale. South Park, Colorado (John Wolfe), and 

 in British America. (Eu.) 



# # Spikes green when mature, aggregated or remote, never in compound heads. 



(Here may be sought forms of No. 59.) MUHLENBERGIAN^E, Tuckm. 



4- Spikes few-flowered, distinct, often remote. 



54. C. tenella, Schk. Tufted and stoloniferous : culms very slender, 

 almost capillary, 6 to 16 inches high, about the length of the narrow, loose 

 leaves: spikes scattered, 1 to ^-flowered : perigynium shortly oval, rounded on the 

 outside, finely nerved, abruptly and minutely beaked, longer than the very thin 

 scale. C. disperma, Dew. C. gracilis, Carey. Swamps throughout. 



55. C. rosea, Schk., var. retroflexa, Torr. Tufted: culms slender, 

 smooth, longer than the narrow leaves: spikes 3 to 8-flowered, mostly approxi- 

 mate, the lower distinct but not remote, stellate in appearance when mature : peri- 

 gynium sessile, ovate-lanceolate, smooth throughout, flnely nerved and spongy- 

 thickened at the base on the inner side, gradually tapering into a toothed beak, at 

 maturity widely spreading or reflexed, a little longer than the very acute scale. 

 C. retroflexa, Muhl. Dry banks and copses, Indian Territory and southward. 

 The species which probably occurs within our limits is distinguished by its 

 more scattered spikes, shorter scales, and scabrous upper angles of the peri- 

 gynium. From its allies, the species and its variety are distinguished by 

 their small and stellate spikes. 



H- - Spikes several to many-flowered, aggregated into a globular or oblong 



head. 



56. C. Cephalophora, Muhl. Cespitose : culms rather stout, rough, rather 

 longer than the narrow leaves : spikes 3 to 6, small, very densely aggregated, 

 the head subtended by a setaceous, rarely leafy bract : perigynium broadly orate, 

 rather abruptly short-beaked, obscurely nerved on the outer side, rough above, 

 mostly longer than the acute or cuspidate scale. Indian Territory and south- 

 westward. 



57. C. Muhlenbergii, Schk. Culm stiff, 1 to 2 feet high, very sharply 

 angled, rough, usually a little longer than the narrow and long-pointed leaves : 



