72 FLOBA OF PHILADELPHIA. 



Pistillate spikes cylindric; achene not longer than thick. 



Perigynia yellowish, tapering into a beak twice as long as the 



body. 6. C. lupuliformis. 



Perigynia greenish-brown, abruptly narrowed into a beak 2-3 times 



as long as the body. 7. C. grandis. 



2. VESICAEIAE. 



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

 Perigynia ascending or spreading, not reflexed. 



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



Leaves 4-12 mm. wide; culm stout. 8. C. utriculata. 



Leaves 2-5 mm. wide; culm slender. 9. C. monile. 



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



10. C. bullata. 

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



11. C. retrorsa. 

 Scales tapering into rough awns, or subulate and scabrous. 



12. C. lurida. 



3. PSEUDOCYPERINAE. 



Spikes all erect or ascending. 13. C. Schweinitzii. 



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



Pistillate spikes oblong-cylindric, 1-5 cm. long; perigynia reflexed. 



14. C. hyfitricina. 

 Pistillate spikes narrowly cylindric, 2.5-6 cm. long; perigynia reflexed. 



15. C. comosa. 



4. SQUARROSAE. 



Scales linear-subulate, longer than the perigynia. 16. C. Franlcii. 

 Scales lanceolate, about one-half as long as the perigynia. 



17. C. squarrosa. 



5. PALUDOSAE. 



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



conspicuous. 18. C. trichocarpa. 



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



19. C. riparia. 



6. SHOETIANAE. 

 7. ANOMALAE. 



8. HIRTAE. 



20. C. Shortiana. 



21. C. scahrata. 



Staminate spike or spikes sessile or nearly so. 22. C. vestita. 



Staminate spike or spikes distinctly stalked. 

 Leaves glabrous; native species. 



Leaves flat or their margins slightly revolute. 

 Scales only half as long as the perigynia. 



23. C. Walteriana. 

 Scales equalling or but slightly shorter than the perigynia. 



24. C. lanuginosa. 

 Leaves strongly involute, 2 mm. wide or less. 



25. C. filiformis. 

 Leaves or their sheaths pubescent; beak long. 26. C. hirta. 



9. ATRATAE. 



27. C. fusca. 



