CYPERACEAE 



203 



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

 Leaf-blades 6-10 mm. wide : si li Ices dense. 

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

 Pistillate spikes oblong : aehenes longer tban thick. 



Perigynia strongly several-nerved, shining : leaf-blades 2-i mm. wide. 

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

 Pistillate spikes cylindric : aehenes not longer than thick. 



4. C iiitumescens. 



5. C. Asa-Grayi. 



6. C. Louisianica. 



7. C. lupuUna. 



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. 

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

 Scales tapering into rough awns. 



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



beak. 

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

 rowed into a beak. 



III. PSEUDOCYPERINAE. 



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

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



9. C. turpescens. 

 10. C. biiUata. 



11. C. lurida. 



12. a Baileyi. 



13. C. hysfricina. 



14. C. cwiwsa. 



IV. SQUARROSAE. 



Scales linear-subulate, longer than the perigynia. 

 Scales lanceolate, J^ as long as the perigynia. 



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



Spikes 2-6, oblong-cylindric, usually staminate at both ends : aehenes 

 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. 



1-5. C. Frankii. 



16. C. squarrosa. 



17. C. typhinoides. 



18. C. trichocarpa. 



19. C. riparia. 



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 i.;^ 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. PENDULIXAE. 



XIII. CRYPTOCARPAE. 



Perigj-nia 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. VIRESCEXTES. 

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



aehene not bent. 

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

 aehene bent or tipped with a bent style. 



20. C. Short imia. 



21. C. scab rata. 



22. C. Jourii. 



23. C. vestita. 



24. C. Walteriana. 



2.5. C. lanuginosa. 



26. C. fiUformis. 



27. a hi'rta. 



28. C.fusca. 



29. C. stricta. 



30. C. iorta. 



31. C. prasma. 



32. C. Uttoralis. 



33. C crinita. 



34. C. gynandra. 



3-5. C. macrokolea. 

 36. C. verrucosa. 



37. C. virescens. 



38. C. costellata. 



39. C. triceps. 



40. C. Caroliniana. 



