C¥PEBACEAE. 61 



New Jersey — Common. 



New Castle— Dixon % etc. Frequent. 



22. Cyperus Grayi Torr. M. p. 166. Barren sands near the coast. Sum- 



mer. 

 New Jersey — Common. 

 New Castle — Collins, Summit Bridge, ComvAons. 



23. Cyperus echinatus (Ell.) Wood. M. p. 166. Dry soil. Summer. 



Fhiladelphia—^sWzst below Navy Yard, Porter (He.), Bartram's Gar- 

 den (P.). 



2. DULICHIUM L. C. Richard. 



1. DuLiCHiUM ARUNDiNACEUM (L.) Britton. M. p. 167. Wet places. 

 Summer. 



3. ELEOCHAEIS E. Br. Spike-Rush. 



Spikelet scarcely or not at all thicker than the culm. 

 Culm stout ; spikelet many-flowered. 



Culm terete, nodose. 1. E. interstincta. 



Culm quadrangular, continuous. 2. E. mutata. 



Culm slender, triangular, continuous; spikelets few-flowered, subulate. 



3. E. EobbinsiL 

 Spikelet manifestly thicker than the culm. 



Style mostly 2-cleft; achene lenticular or biconvex. 



Upper sheath scarious, hyaline ; plants perennial by slender root- 

 stocks. 4. E. olivacea. 

 Upper sheath truncate, oblique, or toothed, not scarious. 

 Annual, with fibrous roots. 



Spikelet ovoid or oblong; tubercle deltoid, acute. 



5. E. ovata. 

 Spikelet oblong-cylindric ; tubercle broad, low. «» 



6. E. Engelmanni. 

 Perennial by horizontal rootstocks. 



Tubercle flat-conic. 



Scape and spike stout. 7. E. palustris. 



Scape and spike slender. 8. E. glaucescens. 



Tubercle swollen, bulb-like ; spikelet not thicker than the 

 scape. ^ ^ 



Style 3-eleft; achene 3-angled or turgid. 

 Achene reticulated or cancellate. 



Spikelet compressed ; culm filiform. 

 Spikelet terete ; culm slender. 

 Achene smooth or papillose. 



Achene smooth, white ; culms capillary. 

 Achene papillose, brown, black, or yellow. 

 Tubercle depressed or short-conic. 

 Achene 3-ribbed on the angles. 

 Achene obtuse-angled, not ribbed. 

 Culm filiform ; scales obtuse. 

 Culm flat ; scales acute. 

 Tubercle subulate or narrowly pyramidal. 



Culms filiform, wiry, densely tufted, 1-2.5 dm. long. 



16. E. intermedia. 

 Culms flattened, slender, 3-6 dm. long. 



17. E. rostellata. 



1. Eleocharis interstincta (Vahl.) R. & S. M. p. 168. Shallow water. 

 Summer. 

 Gloucester— 'Re^a.wpo (He.). 



