50 



CYPEKACEAE. 



Perigynia shorter, usually spreading at maturity, thin- 

 margined. 

 Perigynia little exceeding the scales : entirely staminate 



spikes numerous. 



Perigynia much exceeding the scales : entirely staminate 

 spikes normally absent. 



Perigynia beak 1 /6- 1 /4 the length of the scarcely ser- 

 rulate body, the teeth very short, the suture on 

 inner side inconspicuous : scales very obtuse to 

 acutish. 



Perigynia beak % to nearly the length of the 

 strongly serrulate body, strongly bidentate, the 

 suture conspicuous : scales often sharper. 

 Perigynium-body lanceolate to broadly ovate, 

 narrowed into a beak more than half its 

 length, inconspicuously nerved on inner face. 

 Perigynium-body suborbicular, abruptly con- 

 tracted into a beak less than half its length, 

 conspicuously nerved on inner face. 



VI. O VALES. 



Perigynia narrowly to broadly lanceolate, at least 2% times 



as long as wide. 

 Leaf-blades at most 3 mm. wide, those of sterile shoots 



few, ascending. 

 Leaf-blades broader, those of sterile shoots numerous, 



widely spreading. 

 Tips of perigynia appressed or ascending : spikes 



7-12 mm. long. 

 Tips of perigynia widely spreading or recurved : 



spikes 4-8 mm. long. 

 Perigynia ovate-lanceolate or broader, at most twice as long 



as wide. 

 Perigynia strongly exceeding the scales. 



Perigynia narrowly to broadly ovate, 3-4 mm. long. 

 Perigynia ovate to reniform, 4 mm. or more long. 

 Spikes approximate or scattered, the head stiff : 



scales obtuse or acutish. 

 Spikes in a moniliform flexuous head : scales 



long-pointed. 

 Perigynia equalled by the scales. 



VII. PHYLLOSTACHYAE. 



Body of perigynium oblong : pistillate flowers usually 3-10. 

 Body of perigynium globose : pistillate flowers usually 2-3. 



VIII. POLYTRICHOIDBAB. 



A single species in our range. 



IX. MONTANAE. 



None of the culms short and hidden among the bases of the 



leaves. 

 Lower leaves reduced to sheaths : lower sheaths but 



little flbrillose : plants not stoloniferous. 

 Lower leaves blade-bearing : lower sheaths usually 



strongly flbrillose : plants stoloniferous. 

 Plants long-stoloniferous : staminate spike 12-24 



mm. long. 

 Plants little stoloniferous : staminate spikes 4-12 



mm. long. 



Many of the culms short and hidden among the bases of 

 the leaves. 



A single species in our range. 



X. TRIQUETKAE. 



XI. PEDUNCULATAE. 



A single species in our range. 



11. C. sterilis. 



12. C. interior. 



13. C. Leersii. 



14. C. incomperta. 



15. (7. scoparia. 



16. (7. tribuloides. 



17. C. cristatella. 



18. C. straminea. 



19. (7. festucacea. 



20. C. hormathodes. 



21. C. foenea. 



22. C. Willdenovii. 



23. O. Jamesii. 



24. C. leptalea. 



25. (7. communis. 



26. C. pennsylvanica. 



27. C. varia. 



28. C. umbellata. 



29. C. Mrtifolia. 



30. C. pedunculata. 



XII. PANICEAE. 



Perigynium-beak none or very short, often bent. 



Fertile culm-blades 6-10, 3-7 mm. wide : perigynia more 



