152 



CYPERACEAE 



Spikelets green or brown; superficial cells of the achene 

 quadrate. 

 Scales obtuse or obtusish, appressed. 



Scales membranous, dull; style much exserted. 

 Scales subcoriaceous, shining, style scarcely ex- 

 serted. 

 Scales acute, somewhat spreading at maturity. 



Achene narrowly obovate; spikelets 1-3 cm. long. 

 Achene linear-oblong; spikelets 0.5-2 cm. long. 

 Style 3-cleft; achene 3-angled. 



Scales falling away from the persistent rachis of the flattened 

 spikelets. 

 Wings of the rachis, if present, permanently adnate 

 to it. 

 Scales tipped with recurved awns; low, annual, 



2-15 cm. tall. 

 Scales acute or obtuse, not awned. 



Wings of the rachis none or very narrow. 



Stamens 2 or 3; spikelets linear-oblong, 

 8-25 mm. long. 

 Scales sharply acuminate. 

 Scales blunt, mucronulate. 

 Stamen 1; spikelets ovate, 4-8 mm. long. 

 Wings of the rachis distinct. 



Low annual; adventive from Europe; 



scales brown. 

 Tall indigenous perennials. 



Scales mucronate, reddish brown or 



green. 

 Scales acute or obtuse, not mucronate. 

 Scales wholly or partly purple- 

 brown; achene linear. 

 Scales straw-colored; achene ob- 

 ovoid. 

 Wings of the rachis separating from it as interior 

 scales; annual. 

 Spikelets falling away from the axis of the spikes, the lower 

 pair of scales commonly persistent. 

 Annuals; spikelets elongated, nearly terete. 



Scales imbricated or but slightly distant; achene 

 obovoid. 

 Scales thin, dull brown; spikelets slender. 

 Scales rigid, yellow-brown; spikelets stout. 

 Scales very distant; achene linear-oblong; spikelets 

 very slender. 

 Perennial by hard, tuber-like basal corms; spikelets 

 more or less flattened. 

 Achene narrowly linear-oblong, 3-4 times as long 

 as thick. 

 Spikelets flat, several-many-flowered. 



2. C. diandrus. 



3. C. rivularis. 



4. C. filicinus. 



5. C. microdontus. 



6. C. inflexus. 



7. C. compressus. 



8. C. Iria. 



9. C. psendovegetus. 



10. C. fuscus. 



11. C. dentatus. 



12. C. rotundus. 



13. C. esculentus. 



14. C. erythrorhissus. 



15. C. speciosus. 



16. C.ferax. 



17. C. Engelmanni. 



18. C. strigosus. 



