162 HORDEAE 



3. ELEOCHARIS K. Br. Spike Rush. 



Annual or perennial scapose herbs 6 inches to a foot high, 

 with leaves reduced to basal sheaths, and solitary terminal spikes 

 without subtending bracts; stems cylindric, flattened or angular, 

 grooved, erect and slender; spikelets small; glumes spirally over- 

 lapping; perianth of 1 to 12 bristles; stamens 2 or 3; base of style 

 noticeably swelled and persistent as a tubercle on the lenticular or 

 three-angled achene. 



Style-branches 2. 

 Annual; bristles shorter than the achene: 

 spikes oblong-cylindric; tubercle broad and 



low. 1- E. engehnanni. 



Perennial by roostocks; bristles longer than 

 the achene. 

 Plant stout; tubercle conic triangular. 2. E. pahistris. 



Plant slender; tubercle almost cylindrical. 3. E. glaucescens. 



Style-branches 3. 



Plant very small, 1 to 4 inches high; fruit obo- 

 void oblong, with numerous longitudinal 

 ridges and finer transverse ones. 

 Plants larger, 8 inches high or more. 0. £'. acic^daris. 



Tubercle constricted at the base, clearly dis- 

 tinct from the achene; plant slender, 

 with slender rootstocks.. 4. E. montana. 



Tubercle apparently confluent with the 

 achene. cvlindric; plant stouter, not 

 stoloniferous. -^^ E. rostellata. 



1. EleochariS engelmanni Steud. Not common in New- 

 Mexico. KiiMwii from only I wo collections in the western part of 

 the State in tlif inouiit;uii.<. ]irob;-ibly beside streams. 



2. Eleocharis palustris (L.) R. and S. In wet soil besid* 

 springs and streams and in cienagas. Not restricted to any life zone. 



3. Eleocharis glaucescens (Willd.) In wet soil in the moitn- 

 tains in the r|i|ici- Sonouui and Transition Zones. 



4. Eleocharis montana (H. B. K.) R. and S. The com- 

 monest species of Spike Rush in our range. Occurs in wet soil 

 beside springs and water holes, in cienagas and along streams, 

 kardly at all restricted in vertical distribution from the timbered 

 forests down to the hottest valleys. 



5. Eleocharis rostellata Torr. In wet soil at the lower levels 

 of the soiidi.eni pxit of tlie Slate; m the Lower SoB»ra« Zone. 



