112 CYPERACEAE 



■Spikes one to many ; if one, plant not as above. ' • 



Achenes lenticular and stigmas two: lateral spikes sessile; terminal spike partly 

 pistillate, or if staminate, the lateral spikes short, or heads dioecious. 

 Spike one. 



Spike orbicular to short-ovoid. 4. C.\pit.\t.\e. 



Spike linear. 5. Dioic-^e. 



Spikes more than one. 



Perigynia not white-puncticulate. 



Rootstocks long-creepmg, the culms arising singly or few together. 

 Perigj-nia 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. Foetid.\e. 



Spikes distinct. 7. DiviS.\E. 



Culms becoming decumbent and branching. 



8. Chordorrhiz.\e. 

 Perigj-nia thin or wing-margined, the beak bidentate. 



9. Arex.\ri.\e. 

 Rootstock not long-creeping, the cxilms densely cespitose. 



Spikes androgynous. 



Perigj-nia abruptly contracted into the beak. 



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

 brown. 10. jNIuhlexbergi.^nae. 



Spikes numerous; perigj-nia yellowish or brownish. 



Perigj'iiia yellowish; opaque part of leaf-sheath transversely 



rugulose. 11. Multiflor.\e. 



Perigj-nia brownish; opaque part of leaf-sheath not trans- 

 verselj- rugulose. 12. P.\xicul.\tae. 



Perigj-nia tapering into the beak. 13. STEXORfiVNCH.\E. 



Spikes gj-naecandrous or pistillate or rarelj staminate. 

 Perigj-nia at most thin-edged. 



Perigj-nia spreading at maturitj-. 14. Stellui.atae 



Perigj-nia appressed. 15. Dem'ey.a.nae. 



Perigj-nia narrowlv to broadly wing-margined. 



10. OVALES. 



Peiigynia white-puncticulate. 17. Caxescentes. 



Achenes triangular or lenticular: if lenticular, lower lateral spikes conspicuously 

 peduncled, or terminal spike staminate and lateral spikes elongated. 

 Achenes stronglj constricted at base, roimded at apex. IS. PHYLLftSTACHYAE. 

 Achenes not stronglj- constricted at base, pointed at apes. 



Spike one: perigjnia rounded and beakless at ape.x. 19. Polytrichoideae. 

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

 the apex. 

 Perigynia both coriaceous and shining, the beak obliquely cut. 

 Spike solitary. 20. OBTrs.\.TAE. 



Spikes several. 21. Nitidae. 



Perigj-nia not both coriaceous and shining. 



Spike one: perigynia triangular, glabrous, not refle.xed or flattened. 

 Perigj-nia prominently beaked, flnelv manj--nerved. 



22. RlTESTRES. 



Perigynia nearly beakless, 2-keeled but otherwise nerveless. 



2:5. FiRMK ULMES. 



Spikes one to manj-; when one, perigynia differing from above. 



Perigj-nia closely enveloping the achene, strongly tai>ering at ))ase, 

 pubescent or puberulent; bracts sheathless or nearlj- so. 

 Spike normally one. 



Spikes androgynous; leaf-blades very narrow. 



24. FiLIFOUAE. 



Spikes dioecious. 25. Scirpixae. 



Spikes two or more. 26. jMoxtaxae. 



Perigj-nia not as above: or if so, bracts stronglj^ sheathing. 

 Lowest bract long-sheathing, its blades rudimentarj-. 



Leaf-blades flat; perigynia puberulent or pubescent. 



27. DiGITATAE. 



T^eaf-blades filiform; perigynia glabrous. 



28. Alrae. 



Lowest bract sheathless or long-sheatliing ; if long-sheathing, its 

 blade well-developed. 

 Lowest bract strongly sheathing; perigj-nia never strongly 

 bidentate with stiff teeth. 

 Achenes leiuicular; stigmas two. 29. BiroLORES. 

 Achenes triangular: stigmas three. 

 Scales not dark-tinged. 



Pistillate spikes short-oblong to linear, erect. 



Perigynia tapering at base, triangular, closely 

 enveloping tlie achenes. 

 Rootstock long-creeping. 



30. Paxiceae. 

 Rootstock not long-creeping. 



31. L.\XIFLORAE. 



