174 



CYPERACEAE 



Perigynia 4-9 mm. long, spongy at base; beak 

 longer than body. 

 Perigynia scarcely compressed, nearly terete, 

 whitish green. 

 Spikes gynaecandrous, rarely entirely staminate or 

 pistillate. 

 Perigynia ascending or appressed, the body not 

 margined. 

 Perigynia 4 mm. long or less, puncticulate. 

 Perigynia longer, not puncticulate. 

 Perigynia body with thin or winged margins. 



Perigynia spongy at base, usually spreading at 



maturity. 

 Perigynia not spongy at base, not widely 

 spreading at maturity. 

 2. Achenes triangular or lenticular; if lenticular the lower 

 lateral spikes conspicuously peduncled, or with stami- 

 nate terminal spike and elongated lateral spikes. 

 Scales bract-like; achenes strongly constricted at the base. 

 Scales not bract-like; achenes not strongly constricted at 

 the base. 

 Spike normally 1, the perigynia reflexed, or rounded 

 and beakless at the apex. 

 Perigynia rounded at the apex, beakless, glabrous. 

 Perigynia beaked, strongly reflexed. 

 Spikes i-many, when one the perigynia neither reflexed 

 nor rounded. 

 Perigynia triangular, membranous, closely envelop- 

 ing the achene, essentially nerveless, or 2 

 ribbed; bracts sheathless or nearly so. 

 Perigynia obtusely triangular; foliage not pu- 

 bescent. 

 Young achenes mitrate at apex; lowest 



scales rough awned. 

 Young achenes and lowest scales not as 

 above. 

 Perigynia acutely triangular; foliage usually 

 pubescent. 

 Perigynia not as above; or if so bracts strongly 

 sheathing. 

 A. Lowest bract strongly green-sheathing; peri- 

 gynia beakless to beaked, en tire, oblique or 

 emarginate at apex; or long beaked and 

 apex hyaline, becoming bidentate, teeth 

 weak; achenes triangular, or, if (rarely) 

 lenticular the perigynia dull and sub- 

 terete. 

 Bracts with obsolete or rudimentary blades. 

 Lower spikes nearly radical; scales 

 abruptly cuspidate. 



5. Stenorhynchae. 



6. Tenellae. 



7. Canescentes. 



8. Deweyanae. 



9. Stellulatae. 



10. O VALES. 



11. Phyllostachyae. 



12. Polytrichoideae. 



13. Pauciflorae. 



14. Mitratae. 



15. montanae. 



16. Triquetrae. 



17. Pedunculatae. 



