CYPERACEAE 55 



Perigynia ascending or spreading-, not reflexed. 

 Spikes narrowly cylindric, 6-8 mm. thick, 2-15 cm. long. 

 Stems stout : leaf-blades 4-12 mm. wide. 10. C. utriculata. 



Stems slender : leaf-blades 2-5 mm. wide. 11. Cniontle. 

 Spikes oblong-cylindric or cylindric, 12 mm. thick, 2-5 cm. long. 

 Scales with smooth awns. 12. C. Tuckermanii. 



Scales merely acute or acuminate, or the upper blunt. 



13. C. bullata. 

 Perigynia, at least the lower ones, reflexed at maturity. 

 Spikes clustered at the top of the scape, or the lower i or 2 separated : 



perigynia all reflexed at maturity. 14. C. retrorsa. 



Spikes scattered : perigynia at the base of the spikes reflexed. 



15. C. Hartii. 

 b. Scales tapering into rough awns. 



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



beak. 16. C. lurida. 



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

 into a beak. 17. C. Baileyi. 



IV. PSEUDOCYPERINAE. 

 Spikes erect or ascending. 18. C. Schweinitzii. 



Spikes, at least the lower ones, slender-peduncled and drooping. 



Pistillate spikes oblong-cylindric, 1-3 cm. long : perigj'nia ascending. 



19. C. hystricina. 

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



Perigynium-beak with erect or slightly spreading teeth. 



20. C. Psendo-Cyperus. 

 Perigynium-beak with recurved teeth. 21. C. comosa. 



V. SQUARROSAE. 



Scales linear-subulate, longer than the perigynia. 22. C. Frankii. 

 Scales lanceolate, V^ as long as the perigynia. 

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



23. C. squarrosa. 

 Spikes 2-6, oblong-cylindric, usually staminate at both ends : achenes ovoid. 



24. C. typhinoides. 



VI. PALUDOSAE. 



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

 spicuous. 25. C. trichocarpa. 

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



26. C. riparia. 

 VII. SHORTIANAE. 

 A single species in our range. 27. C. Shortiana. 



VIII. ANOMALAE. 

 A single species in our range. 8. C. scabrata. 



IX. HIRTAE. 

 Staminate spike or spikes sessile or nearly so. 29. C. vestita. 



Staminate spike or spikes distinctly stalked. 

 a. Leaves glabrous : native species. 

 Leaf-blades flat, or their margins slightly revolute. 



30. C. lanugi7iosa. 

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



31. C.filiformis. 



