CYPEKACEAE 



Pistillate spikes oblong-cylindrical. 

 Perigyuia 5 X/ or less long. 

 Perigynia tapering into the long beak. 

 Staminate spikes several. 

 Staminate spike usually one. 



Spikes 6 X/ thick ; perigynia faintly 



nerved. 

 Spikes 4 7/ thick ; perigynia strongly 



nerved. 



Perigynia abruptly narrowed into beak. 

 Scales exceeding perigynia. 

 Perigynia exceeding scales. 

 Perigynia tapering into minute beak. 

 Perigynia thick, scarcely inflated. 

 Perigynia glabrous. 



Perigynia teeth l /x or more long. 

 Scales acuminate. 

 Scales with long cusp. 

 Perigynia teeth 1 // or less long. 

 Perigynia hairy. 



II. 



Perigynia beak short or wanting. 

 Staminate spikes usually two or more. 

 Pistillate spikes erect. 

 Lowest bract 4 / -5 / long. 

 Lowest bract l / -2 / long. 

 Pistillate spikes drooping. 

 Staminate spike one ; pistillate above. 

 Leaves smooth. 

 Leaves hairy. 

 Spikes stout, 6 X/ long. 

 Spikes slender, V long. 

 Staminate spike one ; Staminate throughout. 

 Perigynia beakless or nearly so. 

 Leaves 2"-3" wide. 

 Leaves l"-2" wide. 

 Perigynia with a short, straight beak. 

 Spikes many-flowered. 

 Spikes 12 or fewer- flowered. 

 Sheaths smooth. 

 Sheaths scabrous-pubescent. 

 Perigynia with a short abruptly bent beak. 

 Leaves V-\\" wide. 

 Upper scales obtuse. 

 Upper scales acute. 

 Leaves 6 7/ or more wide. 

 Perigynia beak stout, half the length of the body 



or more. 



Culms exceeding the leaves. 

 Plant strongly pubescent. 

 Plant glabrous. 

 Staminate spike 6 // -\2 // long. 

 Staminate spike 2 // -4" long. 

 Cnlms much shorter than the leaves. 

 Pistillate spikes several-flowered. 

 Pistillate spikes 1-3-flowered. 



2. C. lupulina. 



3. C. monile. 



4. C. lurida. 



5. C. hystricina. 



6. C. Frankii. 



7. C. typhinoides. 

 17. C. Davuii. 



8. C. trichocarpa. 



9. G. aristata. 



10. C. riparia. 



11. C. Januginosa. 



12. C. stricta. 



13. C. Haydeni. 



14. C. gynandra. 



15. C. Shortiana. 



16. C. hirsuta. 



17. C. Davisii. 



18. C. grisea. 



19. C. amphibola. 



20. C. granularis. 



21. C. oligocarpa. 



22. C. Htichcockiana. 



23. C. Meadii. 



24. C. laxiflora. 



25. C. Albursina. 



29. C. pubescens. 



26. C. Pennsylvanica . 



27. C. varia. 



28. C. umbellata. 



30. C. Jamesii. 



