SEDGE FAMILY. 



249 



2. Eleocharis mutata (I,.) R. & S. Quadrangular Spike-rush. ( Fig. 578.) 



Scirpus mulatiis L. Am. Acad. 5: 391. 1760. 

 Sci>~f>us quadrang ulatus Michx. Fl. Bor. Am. i: 30 



1803. 



Eleocharis quadrangulata R. & S. Syst. a: 155. 1817. 

 Eleocharis niutala R. & S. Syst. a: 155. 1817. 



Perennial by stout rootstocks, culms sharply 4- 

 angled, stout, not nodose, papillose, 2-4 tall. 

 Sheaths purplish-brown or green, membranous, 

 sometimes bearing short blades; spikelet terete, 

 acute, cylindric, i'-2' long, 2" in diameter, many- 

 flowered, about as thick as the culm; scales coria- 

 ceous, broadly ovate or obovate, obtuse or the upper 

 subacute, scarious-margined and sometimes with a 

 narrow brown band within the margins, faintly 

 many-nerved, persistent; bristles about 6, rigid, re- 

 trorsely barbed, about as long as the achene; sta- 

 mens 3; style 3-cleft; achene obovoid, biconvex or 

 slightly angled on the back, minutely cancellate, 

 about twice as long as the conic acute tubercle, 

 which is truncate or contracted at the base. 



In ponds, streams and swamps, northern New Jersey to Michigan, south to Alabama, 

 Texas and Guatemala. Also in the West Indies and South America. July-Sept. 



3. Eleocharis Robbinsii (.takes. Robbtns* 

 Spike-rush. (Fig. 579.) 



Eleocharis Robbinsii Oakes, Hovey's Mag 7: 178. 1841. 



Perennial by slender rootstocks, culms si end r 

 angled, continuous, 6'-2 long, sometimes producing 

 numerous filiform flaccid sterile branches from the DMT. 

 Sheaths appressed, obliquely truncate; spikelet subulate, 

 few-flowered, not thicker than the culm, 6"-io" long, 

 \" in diameter; scales lanceolate or oblong-lanceolate, 

 obtuse or subacute, strongly concave, faintly several- 

 nerved, persistently clasping the rachis. narrowly cari- 

 ous-margined; style 3-cleft; bristles 6, equalling lh 

 achene and tubercle, retrorsely barbed ; achene obovoid, 

 light brown, biconvex or very obtusely angled on the 

 back, somewhat longer than the conic -subulate flattened 

 tubercle, which has a raised ring around its base. 



In shallow water, New Brunswick to Michigan, sooth to 

 Florida. Aug. -Sept 



4. Eleocharis ochreata (Nees) Steud. Pale Spike-rush >8o. ) 



Eleogenus ochreatus Nees in Mart. Fl. Bras, a: Part i, 



102. 1842. 

 Eleocharis ochreata Steud. Syn. PI. Cyp. 79. 1855. 



Perennial by very slender rootstocks, culms very 

 slender, or filiform, erect, pale green, 3-angled, 2 / -io / 

 tall. Upper sheath with a white, hyaline, scarious 

 limb; spikelet oblong or ovoid, subacute, 2-3 times as 

 thick as the culm, about 2" long, i#" in diameter, 

 several-flowered ; scales pale green, oblong-lanceolate, 

 obtuse or the upper acute, thin, hyaline with a faint 

 mid vein; style 2-cleft; bristles about 6, slender, re- 

 trorsely barbed, somewhat longer than the achene; 

 achene %" long, lenticular, obovate, smooth, brown 

 2-4 times as long as the conic acute tubercle, which 

 is often constricted at the base. 



In wet soil, southern Virginia to Florida and 

 sippi. Also in Wyoming and Montana and in tropical 

 America. Aug. -Sept. 



