CYPEKACEAE 



203 



Leaf-blades 4-6 mm. wide : spikes loosely flowered. 4. C. intumescem. 



Leaf-blades 6-10 mm. wide : spikes dense. 5. C. Asa-Grayi. 

 B. Pistillate spikes oblong or cylindric, densely many-flowered. 

 Pistillate spikes oblong : achenes longer than thick. 



Perigynia strongly several-nerved, shining : leaf-blades 2-4 mm. wide. 6. C. Louisianica. 



Perigynia many-nerved, dull : leaf-blades 4-10 mm. wide. 7. C. lupulina. 



Pistillate spikes cylindric : achenes not longer than thick. 8. C. grandis. 



II. VESICARIAE. 



Scales acute, acuminate or smooth-awned, or the lower slightly roughened. 



Spikes few-several-flowered : perigynia little inflated, gradually beaked. 9. C. turgesccns. 

 Spikes many-flowered : perigynia much inflated, abruptly beaked. 10. C. bullata. 



Scales tapering into rough awns. 



Spikes stout-cylindric, about 12 mm. thick : perigynium tapering into a 



beak. 11. C. lurida. 



Spikes narrowly cylindric, 6-8 mm. thick : perigynium abruptly nar- 

 rowed into a beak. 12. C. Baileyi. 



III. PSEUDOCYPERINAE. 



Pistillate spikes oblong-cylindric, 1-3 cm. long : perigynia ascending. 13. C. hystricina. 



Pistillate spikes narrowly cylindric, 3-7 cm. long : perigynia reflexed. 14. C. comosa. 



IV. SQUARROSAE. 



Scales linear-subulate, longer than the perigynia. 

 Scales lanceolate, % as long as the perigynia. 



Spikes 1-3, subglobose or oval, staminate below : achenes linear-oblong. 



Spikes < 2r-&, oblong-cylindric, usually staminate at both ends: achenes 

 ovoid. 



V. PALUDOSAE. 



Leaves bright green, not glaucous : teeth of the perigynium-beak slender, 



conspicuous. 

 Leaves pale green, glaucous : teeth of the perigynium-beak short. 



15. C. Fmnkii. 



16. C. squarrosa. 



17. C. typhin&ides. 



18. C. trichocarpa. 



19. C.ripana. 



A single species in our range. 



VI. SHORTIANAE. 

 VII. ANOMALAE. 



Perigynia ovoid, longer than the scales. 



Perigynia short-obovate, about equalling the serrate-awned scales. 



VIII. HIRTAE. 



Staminate spike or spikes sessile or nearly so. 

 Staminate spike or spikes distinctly stalked. 

 Leaves glabrous : native species. 



Leaf-blades flat, or their margins slightly revolute. 

 Scales only % as long as the perigynia : coast species. 

 Scales as long as the perigynia or only slightly shorter : Alleghenian 



species. 



Leaf- blades strongly revolute, 2 mm. wide or narrower. 

 Leaves, at least their sheaths, pubescent : naturalized species. 



A single species in our range. 

 A single species in our range. 



IX. ATRATAE. 



X. RIGIDAE. 



XI. PRASINAE. 



Perigynia twisted toward the top : scales purple-brown. 

 Perigynia straight : scales green. 



A single species in our range. 



XII. PENDULINAE. 



XIII. CRYPTOCARPAE. 



Perigynia nerveless or faintly nerved, much shorter than the scales. 



Perigynia obovoid, obtuse. 



Perigynia oblong or elliptic, acute. 

 Perigynia strongly several-nerved, about equalling the scales in length. 



Spikes erect. 



Spikes drooping, filiform -stalked. 



XIV. VIRESCENTES. 

 Perigynia densely pubescent. 



Pistillate spikes oblong-cylindric, 8-20 mm. long : perigynia oval or 



ovoid, few-nerved. 

 Pistillate spikes narrowly cylindric, 12-36 mm. long : perigynia oblong, 



strongly many-nerved. 

 Perigynia glabrous or nearly so, at least when mature. 



Spikes 5-7 mm. thick : perigynia imbricated, flattened : top of the 



achene not bent. 



Spikes 3-4 mm. thick : perigynia not imbricated, swollen : top of the 

 achene bent or tipped with a bent style. 



20. C. Short iana. 



21. C. scabrata. 



22. C. Joorii. 



23. C. vestita. 



24. C. Waltcriana. 



25. C. lanuginosa. 



26. C.filiformis. 



27. C. hirta. ' 



28. C.fusca. 



29. C. stricta. 



30. C. torta. 



31. C.prasina. 



32. C. littoralis. 



33. a crinita. 



34. C. gynandra. 



35. C. macrokolea. 



36. C. verrumsa. 



37. C. virescens. 



38. C. costellata. 



39. C. triceps. 



40. C. Caroliniana. 



