CYPERACEAE ' 21 



4. Cyperus schweinitzii Torr. 



Common in dry sandy prairies. Arapahoe; Broken Bow; Franklin; 

 Foster; Louisville; Minden; Plummer Ford; Tliedford. 

 5. .Cyperus acuminatus Torr & Hook. 



Common in moist soil over most of the state. Edgar; Ewing; Frank- 

 lin; Lincoln; Loup City; Minden; Valentine. 



6. Cyperus esculentus L. 



Common in moist soil over most of the state. Callaway; Ewing; Ken- 

 nedy; Lincoln; Wood Lake; Grand Rapids. 



7. Cyperus erythrorhizos Muhl. 



In wet soil in the eastern part of the state. Ewing; Lincoln; Niobrara 

 River; Norfolk. 



8. Cyperus speciosus Vahl. 

 Cyperus ferax Rich. 



In marshes in the southeastern part of the state. Hardy; Lincoln; 

 Repuhlican Valley. 



9. Cyperus strigosus L. 



Over most of the state, common along streams in the sand-hills. Cody's 

 Lake; Ewing; Nebraska City; Niobrara River; Republican; Thedford. 



10. Cyperus filiculmis Vahl. 



Fairly common in the eastern part of the state. Ewing; Hardy; Lin- 

 coln; Louisville; Minden; Nebraska City; Republican. 



11. Cyperus houghtonii Torr. 

 Xattick. 



10. Carex. 189. 

 Achenes mostly triangular, never lenticular, stigmas three. 

 Perigynia long-beaked — beak usually as long as body. 

 Perigynia gradually narrowed into a beak. 

 Perigynium not hard or leathery. 



Beak without long stiff or spreading teeth, sometimes entire. 

 Beak 2-toothed. 



Perigynia about 12 mm. long. 1. C. lupulina. 



Perigynia about 8 mm. long. 2. C. lurida. 



Beak entire. 29. C. durifolia. 



Beak with stiff, setaceous, or awn-like teeth. 



Teeth short, little spreading. 3. C. hystericina. 



Teeth 1 m_m. long, spreading. 4. C. comosa. 



Perigynia hard or leathery. 6. C. trichocarpa. 



Perigynia abruptly contracted into a beak. 



Scales about as long as perigynium, spikes not globose. 



17. C. longirostris. 

 Scales about half as long as perigynium, spike globose. 



5. C. squarrosa. 

 Perigynia with short beaks, usually not more than half as long as 

 the body; or beakless. 

 Perigynia with 2-toothed beaks. 

 Perigynia glabrous or nearly so. 



Perigynia 2-3 mm. long, twice as long as scales. 39. C. rosea. 

 Perigynia 4-5 mm. long, about as long as the scales. 



Leaves pubescent, terminal spike staminate at the base. 



16. C. davisii. 



