46 



CYPERACEAE 



Pistillate spikes obloiig-cyliudrical. 

 Perigynia 5" or less long. 



Perigjnia tapering into the long beak. 

 Staniiuate sj)ikes several. 

 Staniinate spike usually one. 



Spikes 6" thick ; perigynia faintly 



nerved. 

 Spikes AV^ thick ; perigynia strongly 

 nerved. 

 Perigynia abruptly narrowed into beak. 

 Scales exceeding perigynia. 

 Perigynia exceeding scales. 

 Perigynia tapering into minute beak. 

 Perigynia thick, scarcely iufiated. 

 Perigynia glabrous. 



Perigynia teeth 1" or more long. 

 Scales acuminate. 

 Scales with long cusp. 

 Perigynia teeth V^ or less long. 

 Perigynia hairy. 



II. 

 Perigynia beak short or wanting. 

 Staminate spikes iTSually two or more. 

 Pistillate spikes erect. 

 Lowest bract 4'-5' long. 

 Lowest bract 1^-2' long. 

 Pistillate spikes drooping. 

 Staminate spike one ; pistillate above. 

 Leaves smooth. 

 Leaves hairy. 

 Spikes stout, 6'^ long. 

 Spikes slender, 1' long. 

 Staminate spike one ; staminate throughout. 

 Perigj'nia beakless or nearly so. 

 Leaves 2''-3'^ wide. 

 Leaves l^'-2'' wide. 

 Perigynia with a short, straight beak. 

 Spikes many-tlowered. 

 Spikes 12 or fewer- flowered. 

 Sheaths smooth. 

 Sheaths scabrous-pubescent. 

 Perigynia with a short abruptly bent beak. 

 Leaves ^"-AV' wide. 

 Upper scales obtuse. 

 Upper scales acute. 

 Leaves Q" 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 r)'^-12'' long. 

 Staminate spike 2"-4'' long. 

 Culms much shorter than the leaves. 

 Pistillate spikes several-flowered. 

 Piatillate spikes 1-3-llowered. 



2. C. lupulina. 



3. C. moil He. 



4. C. lurida. 



5. C. hi/striciua. 



6. a Frankii. 



7. C. (i/phinoiJes. 

 17. C. baiisii. 



8. C. irichocarpa. 



9. C. arititatd. 



10. C. riparia. 



11. C. lanuginosa. 



12. C. fitrida. 



13. C. Haydeni. 



14. C. gynandra. 



15. C. Sliortiana. 



16. C. hirsuta. 



17. C. Davimi. 



18. C. grisea. 



19. C amphihola. 



20. C. granularis. 



21. 0. oligocarpa. 



22. C. Hifvhcockia7ia. 



23. C. Mmdii. 



24. C. loivijlora. 



25. C. Albnrsiiia. 



29. C pubesccns. 



26. C. Pennsylvanica. 



27. C. varia. 



28. C. ninhrlldta. 



30. C. Javienii. 



