20 POALES 



7. Eriophorum. 1S0. 



Leaves 1.5 mm. wide or less, spike in fruit not over 2 cm. long. 



1. E. gracile. 

 Leaves 1.5-4 mm. wide, spike in fruit 2.5-4, 5 mm. long. 



2. E. angustifolium 



1. Eriophorum graciie Roth. Slender Cotton Grass. 

 In wet soil in the sand-hill regions. Kennedy; Lavaca; Simeon; 

 Thedford. 



2. Eriophorum angustifolium Roth. 

 Arabia; Kennedy. 



8. Dulichium. 166. 



1. Dulichium arundinaceum (L.) Britton. 



In wet soil, not common. Bone Creek Valley; Endicott; Ewing; Ken- 

 nedy. 



9. Cyperus, 159. 



Styles 2-cleft; achenes lenticular. 



Styles long exserted; scales dull; stamens usually 3. 1. C. diandrus. 

 Styles scarcely exserted; scales shiny; stamens mostly 3. 



2. C. rivularis. 

 Styles 3-cleft; achenes 3-angled. 



Annuals without corms or rootstocks. 

 Spikelets in simple umbels; stamen 1. 



Tips of the scales awnlike, recurved. 3. C. inflexus. 



Tips of the scales not prolonged into awns. 5. C. acuminatus. 

 Spikelets in compound umbels; stamens 3. 



Wings of the rachilla persistent, embracing the achenes; spike- 



3-19 mm. long. 7. C. erythrorhizos. 



Wings of the rachilla persistent, embracing the achenes; sqipe- 



lets terete, 5-18 mm. long. 8. C. speciosus. 



Perennials with corms or rootstocks. 



With scaly tuber-bearing rootstocks. 6. C. esculentus. 



Without rootstocks, perennial by basal corms. 



Achene 3-4 times as long as wide. 9. C. strigosus. 



Achenes about twice as long as wide. 



Spikelets flat, in loose spikes at the ends of the rays of the 



umbels. 4. C. schwelnitzil. 



Spikelets terete, or compressed, in capitate clusters on the 



rays. 



Scales pale green. 10. C. filiculmis. 



Scales brown, shining. 11. C. houghtonii. 



1. Cyperus diandrus Torr. 



Com.mon along streams over most of the state. Callaway; Franklin; 

 Kennedy; Long Pine; St. Paul; Valentine. 



2. Cyperus rivularis Kunth. 



Common in wet soil throughout the state. Minden; Nebraska City; 

 Pishelville; Richardson County; Thedford; Valentine. 



3. Cyperus inflexus Muhl. 

 Cyperus aristatus Rothb. 



Occurs over the whole state, but most abundant in the sand-hills, 

 Callaway; Franklin; Lincoln; Mullen; Pine Ridge; Red Cloud; Thed- 

 ford, 



