FLORA OF WASHINGTON AND VICINITY. 125 



Cyperus erythrorhizos, Muhl. 



Custis Spring, September 29, 1878. 



Cyperus virens, Michx. 



Flats lielow Eads' Mill. First half of August . 



Cyperus phymatodes, Muhl. 



This species invades the city and springs up in lawns, parks, &c., where the 

 ground is somewhat moist. July to September. 



t Cyperus strigosus, L. 



Common. A depauperate form with very short (4'"™), one to few flowered spikes 

 probably belongs to this species. August, September. 



Cyperus Michauxianus, Schultes. 



Custis Spring. September 29, 1878. 



t Cyperus filiculmis, Vahl. 

 June to August. 



Cyperus Lane astriensis, Poiter. 



Well defined forms of this sjjecies occur, but also sever al aberrant forms, appar- 

 ently connecting it with C. retrojiexus. July to September. 



t Cyperus ovxilaris, Torr. Hedge-hog Club-Rush. 

 July to September. 



t Cyperus retrofractus, Torr. 



Varies greatly in the length and size of the spikes, and perhaps the large-spiked 

 forms should all be referred to C. Lancastriensis. July to September. 



IDxilichium spathaceum, Pers. 

 Last half of July. 



tFuirena squarrosa, Michx. Umbrella-Grass. 

 Holmead Swamp. July, August. 



tEleocharis quadrangulata, R. Br. Spike-Rush. 



Eastern Branch opposite the Race Course. July, August. 



tEleocharis obtusa, Schultes. 



Spikes variable in size. May to July. 



Eleocharis palustris, R. Br. 

 May. 



Eleocharis compressa, SuUiv. 



Little Falls; Great Falls; in damp, rocky places. The descriptions of this species 

 in the fourth and fifth editions of Gray's Manual differ in some essential respects, 

 and our plant agrees better with the former. The achenium is triangular-obovate 

 and conspicuously pitted with oblong depressions longitudinally arranged. Stigmas 

 often 3. It seems to be intermediate between E. compressa aud E. rostellata. Middle 

 to end of May. 



t Eleocharis tenuis, Schultes. 

 First half of May. 



Eleocharis aciciilaris, R. Br. 



Bottom of dried ponds. June, July. 



