3. Eleocharis acicularis (L.) R. & S. Fig. 1 87. 



Rhizomatous perennial forming mats; roots not fleshy; rhizomes 0.3-0.6 mm. 

 thick, extensively creeping; aerial culms 2-23 cm. long, 0.2-0.4 mm. thick, about 

 8-costate and -sulcate, often somewhat flattened or angulate; sheaths thin, reddish 

 below, pallid and membranous or hyaline terminally, oblique; spikelets narrowly 

 ovoid to ovoid-elliptic, 2-5 mm. long, 5- to 15-flowered; scales membranous, whit- 

 ish to usually dark-purplish-red (or marginally pallid), ovate, 1.5-2 mm. long, 

 rather truncate to acute; bristles 3 or 4, or usually (in Texas material) reduced or 

 absent; stamens 3, anthers 0.5-1 mm. long; styles 3-branched; achenial body 

 obovoid, obscurely trigonous to usually nearly terete because of the turgid sides, 

 0.5-0.7 mm. long, pearly-white, with a number of longitudinal ribs and between 

 each 2 ribs 25 to 40 close horizontally elongate facets or cells; tubercle conic, 

 0.075-0.15 mm. long, constricted basally, much narrower than the achenial body. 

 E. Reverchonii Svens. 



Muddy river banks, meadows, vernal pools, edge of lakes and marshes, in Okla. 

 (Kay and Alfalfa cos.), nearly throughout Tex. except Trans-Pecos and e. Tex., 

 N. M. (San Miguel, Rio Arriba, Catron, San Juan, Socorro and Grant cos.) and 

 Ariz. (Apache and Coconino cos.), infrequent or locally abundant, Feb.-summer; 

 most n.-temp. areas of the world, in Am. s. to Calif., Chih., and the Gulf States. 



4. Eleocharis radicans (A. Dietr.) Kunth. Fig. 187. 



Densely matted perennial, the rhizomes very short; culms succulent (pressed 

 flat in specimens), only 3-8 cm. long, 0.6-1 mm. thick, erect; sheaths mem- 

 branous, tight; spikelets ovoid, 3-4 mm. long, 6- to 12-flowered; scales ovate- 

 lanceolate, greenish-stramineous; bristles usually 4, slender, white, retrorsely 

 toothed, variable in length, in some specimens reduced or absent; stamens 2, 

 anthers 0.3-0.4 mm. long; style 3-branched; achenial bodies narrowly obovoid, 

 0.7-0.9 mm. long, pearly, obscurely trigonous or usually essentially terete, with 

 several longitudinal ridges and (between them) many (30 to 40) close horizon- 

 tally elongate cells (trabeculae) in each longitudinal series; tubercle conic, 0.1-0.2 

 mm. long, much narrower than the body. Scirpus radicans Poir. (an illegit. name), 

 Eleogiton radicans A. Dietr., Eleocharis Lindheimeri (Clarke) Svens. 



Rare in marshy areas, wet sand and gravelly stream banks, in Okla. {Waterfall), 

 e. and s.e. Tex. and Ariz. (Coconino, Pinal and Cochise cos.), spring (-summer?); 

 Va., Mich., Tex., Okla., Ariz., Calif., Son., Gr. Ant., S.A.; H.I. 



5. Eleocharis bella (Piper) Svens. 



Dwarf annual with fibrous roots and caespitose culms, often forming dense 

 round tufts 5-10 cm. in diameter; culms capillary, furrowed, 2-6 cm. tall, light 

 green; basal leaf sheaths loose, obliquely truncated; spikelets 1-3 mm. long, 3- to 

 15-flowered; scales with purplish brown sides and green midrib; bristles none; 

 stamens 2, anthers 0.25-0.4 mm. long; stigmas 3; achenes white or cream-colored, 

 0.6-0.8 mm. long, with numerous longitudinal ribs, about 30 fine transverse lines 

 between the ribs; tubercle compressed-conical. 



Montane meadows, borders of marshes and lakes, wet, muddy or springy places, 

 in Ariz. (Apache, Coconino and Cochise cos.); Mont., Ida. and Wash., s. to N.M. 

 and Ariz. 



6. Eleocharis quadrangulata (Michx.) R. & S. Fig. 188. 



Tufted perennial; culms 5-8 dm. long, 2.5-4 mm. thick, erect, sharply 4-angled, 

 not septate; sheaths membranous, brownish or less commonly reddish, apically 

 oblique; spikelets cylindric, 20-42 mm. long, 3.5-4.5 mm. thick, with 40 to 90 

 flowers; scales rotundly obovate to ovate, 5.5-6 mm. long, 3-5 mm. broad, 

 medially nearly flat, stramineous and subcartilaginous, laterally broadly chartace- 



372 



