CYPERACEAE (SEDGE FAMILY) 



3 a Spikelets conspicuously flattened i. Cyperus. p 123 



b Spikelets not conspicuously flattened 4 



4 a Spikelets 5-io-flowered, usually not more than 1 A in. long 5 

 b Spikelets if-so-flowered, */4 in. or more long 6 



5 a Plant 2-10 in. high, densely tufted 4. Stenophyllus. p 124. 

 b Plant 1-3 ft. high, not densely tufted.. 9. Cladium. p 125 



6 a Plants slender; achenes variously marked with ridges 



5. Fimbristylis. p 124. 

 b Plants comparatively stout; achenes smooth 



6. Scirpus. p 124 



7 a Spikelets clustered in narrow spikes, arranged in the 



axils of the leaves 2. Dulic/iium. p 124. 



b Spikelets not completely as in a 8 



8 a Spikelets clustered, appearing lateral on a leafless stem 



6. Scirpus. p 124. 

 b Spikelets not completely as in a 9 



9 a Spikelets with long silky hairs in fruit; stems wiry 



7. Eriophorum. p 124 

 b Spikelets not with long silky hairs in fruit 10 



a Pistillate spikes spindle-shaped, few-flowered; achene 



subtended by barbed bristles.. 8. Rhynchospora. p 124. 

 b Pistillate spikes comparatively small, i-flowered ; no 



bristles subtending the achene 10. Scleria. p 12$ 



c Pistillate spikes various; achenes surrounded by a papery 



membrane; no bristles subtending the achene 



u. Car ex. p 125 



1 CYPfeRUS. 



1 a Plant cultivated in aquaria or pots 



UMBRELLA PLANT. (C. alter nifblius.*) 

 b Plants not cultivated as in a 2 



2 a Tips of scales on spikelets spreading causing spikelets to 



appear toothed ; the scales often modified into leaves 



TOOTHED CYPERUS. (C. dentatus.) 

 b Spikelets not completely as in a 3 



3 a Branches of mature umbel 2 in. or less long 4 



b Some branches of mature umbel 3 in. or more long. ... 7 



4 a Spikelets in a globose head. GLOBOSE CYPERUS. (C. ovularis.) 

 b Spikelets not in a globose head 5 



5 a Spikelets about i in. long, very flat 



NUTTALL'S CYPERUS. (C. nuttalli.) 

 b Spikelets about l /2 in. long 6 



6 a Spikelets yellow YELLOW CYPERUS. (C. flavescens.) 



b Spikelets green or brown Low CYPERUS. (C. didndrus.) 



7 a Spikelets ^4 in. or less long, in loose heads 



GRAY'S CYPERUS. (C. grayi.) 

 b Spikelets about Vz in. or more long 8 



123 



