48 HYDRALES 



Fourth scale with a long bent awn, twisted at the base. 



Empty scales hispidulous all over, hairs on rachis internodes 2 

 mm. long. 2. A. furcatus. 



Empty scales smooth except on the nerves, hairs on rachis inter- 

 nodes 3-4 mm. long. 3. A. chrysocomus. 

 Fourth scale awnless or with a short, straight, untwisted awn. 

 Pedicles and rachis internodes with copius, stiff, marginal hairs. 



4. A. haliii. 

 Pedicles and rachis internodes with scant, lax, marginal hairs. 



5. A. paucipilus. 



1. Andropogon scoparius Michx. Little blue-stem. 

 Common on the prairies all over the state. Anselmo; Deuel County; 

 Dismal River; Grand Rapids; Halsey; Lincoln; North Platte; Repub- 

 lican; Valentine. 



2. Andropogon furcatus Muhl. Big blue-stem. 

 Common in prairies throughout the state. Beaver Creek in Holt 

 County; Franklin; Gage County; Halsey; Lincoln; Mullen; Thedford; 

 Wahoo; Whitman; Valentine. 



3. Adropogon chrysocomus Xash. 

 Halsey, 



4. Adropogon Hallil Hack. Big blue-stem. 

 Common on high prairies in the central and western parts of the state. 

 Antelope County; Banner County; Box Butte County; Chelsea; Gar- 

 den County; Haigler; Lawrence Fork; Long Pine; Plummer Ford; 

 Thedford; Valentine. 



5. Andropogon paucipilus Xash. 

 Nebraska, according to Britton's Manual. 



2. Sorghastrum. 71. 



1. Sorghastrum avenaceum (Michx.) Nash. 



Sorghastrum nutans (L.) Nash. 

 Common on the prairies. Ayr; Cams; Dismal River; Deuel County; 

 Hardy; Halsey; Lincoln; North Platte; Thedford; Valentine. 



Tribe 10. Maydeae. 

 1. Tripsacum. 67. 



1. Tripsacum dactyioides L. 



In low wet places in the southeastern part of the state. Nemaha; 



Richardson County; Weeping Water. 



HYDRALES. 



HYDROCHARITACEAE. 

 Philotria. (Elodia.) 60. 



1. Philotria canadensis (Michx.) Britton. 



In ponds and streams, rare. Ewing; Neligh. 



IRIDALES. 



Stamens 6. 1. Amaryllldaceae. 



Stamens 3. 2. iridaceae. 



