112 CYPERACEAE 



4. Capitatae. 



5. DiOICAE. 



Kes one to many; it one, plant not as above. 



Achenes_ lenticular and stigmas two; lateral spikes sessile; terminal 



pistillate, or if staminate. the lateral spikes short, or heads dio€ 

 Spike one. 



Spike orbicular to short-ovoid. 

 Spike linear. 

 Spikes more than one. 



Perigynia not white-pxmcticulate. 



Rootstocks long-creeping, the culms arising singlv or few together. 

 PengjTua not thin or wing-margined, the beak obliquely cut. 

 Culms not branching. 



Spikes densely aggregate into a globular-ovoid head, appearing 



like one spike. 6. Foetidae. 



Spikes distinct. 7. Divisae. 



Culms becoming decumbent and branching. 

 _, . . , 8. Chordorrhizae. 



Pengyma thin or wing-margined, the beak bidentate. 



T3 , ^ - ^ , 9. Arexariae. 



Kootstock not long-creeping, the culms densely cespitose. 

 Spikes androgynous. 



Perig>-nia abruptly contracted into the beak. 



Spikes few (ten or less) ; perigynia green or tinged with reddish 



brown. 10. Muhlenbergiaxae. 



Spikes numerous; perig>-nia yellowish or brownish. 



Perigynia yellowish ; opaque part of leaf-sheath transversely 



nigulose. 1 1 . MULTIFLOR AE. 



Perigynia brownish; opaque part of leaf-sheath not trans- 

 . ^ versely rugulose. 12. Paniculatae. 



Perigynia tapering into the beak. 13. Stexorhynchae. 



Spikes gynaecandrous or pistillate or rarely staminate. 

 Pengj-nia at most thin-edged. 



Perigynia spreading at maturity. 14. Stellulatae. 



Pengyma appressed. 15. Deweyaxae. 



PerigjTiia narrowly to broadly wing-margined. 

 T>^ . • , .^ 16. O vai.es. 



Ar^h^n^c f -^^"^^^ wbite-puncticulate. 17. Caxescentes. 



Acnenes triangular or lenticular; if lenticular, lower lateral spikes conspicuously 



AovE ^^J^^*^' ?^ terminal spike staminate and lateral spikes elongated. 

 Acnenes strongly constricted at base, rounded at apex. 18. Piiyllostachyae. 

 Achenes not strongly constricted at base, pointed at apex. 



gpiice one; perigj-nia rounded and beakless at apex. 19. Polytrichoideae. 



tjpikes one or more; when one, perigynia not both rounded and beakless at 



the apex. 



Perigynia both coriaceous and shining, the beak obliquelv cut. 



Spike sohtary. 20. Obtusatae. 



Spikes several. 21 Nitidae 



PerigjTua not both coriaceous and shining. 



Spike one; perig>Tiia triangular, glabrous, not reflexed or flattened. 

 Perigj-nia prominently beaked, finely many-nerved. 



T, . . 22. RUPESTRE-S. 



Perigj^ia nearly beakless, 2-kecled but otherwise nerveless. 



o ., ^ 23. FlRMTCULMES. 



apikes one to many; when one, perigynia differing from above. 



Pengj-nia closely enveloping the achene, stronglv tapering at base, 



pubescent or puberulent; bracts sheathless or nearly so. 

 Spike normally one. 



Spikes androgynous; leaf-blades very narrow. 



^, ., J. . 24. FiLiroUAE. 



Spikes dioecious. 25. SriRPiXAE. 



Spikes two or more. 20. Moxtaxae. 



A'erigyma not as above; or if so, bracts stronglv sheathing, 

 l^owest bract long-sheathing, its blades rud'imentary. 



i.eaf-blades flat; perigynia puberulent or pubescent. 



, - , , , ^, 27. DIGITATAE. 



T.eaf-blades filiform; perigynia glabrous. 



T , ^ , 28. Albae. 



i^owest^ bract sheathless or long-sheathing; if long-sheathing, its 



blade well-developed. 

 Lowest bract strongly sheathing; perigynia never strongly 



bidentate with stiff teeth. 



Achenes lenticular: stigmas two. 29. Bicolores. 

 Achenes triangidar; stigmas three. 

 Scales not dark-tinged. 



Pistillate spikes short -oblong to linear, erect. 



Perigynia tapering at base, triangular, closely 



enveloping the achenes. 

 Rootstock long-creeping. 



30. Paxiceae. 

 Rootstock not long-creeping. 



31. Laxiflor. 



