32(29). Body of achene 1.2-1.8 mm. long; tubercle 0.2-0.7 mm. long; styles 

 mostly 2-branched, rarely 3-branched (33) 



32. Body of achene 0.7-1.2 mm. long; tubercle 0.1-0.2 mm. long; styles 3- 



branched (34) 



33(32). Styles always 2-branched; body of achenes very faintly reticulate- 

 punctulate to essentially smooth; common 15. E. macrostachya. 



33. Styles 2- or 3-branched; body of achene distinctly reticulate-punctulate; ex- 



ceedingly rare 32. E. fallax. 



34(32). Culms 30-45 cm. long, with complete septa at regular short intervals 

 (as revealed by dissection); body of achene with at least 2 distinct 

 angles, the third sometimes also fairly sharp, the surface essentially 



smooth; scales merely acute, about 2 mm. long 



33. E. austrotexana. 



34. Culms 8-28 cm. long, not septate; body of achene obscurely trigonous, ;he 



surface somewhat punctulate-reticulate; scales with long-acuminate 

 scarious or hyaline apexes which often become split (bifid) during 

 elongation (35) 



35(34). Culms strongly compressed, 0.6-1 mm. thick in the flat dimension; deep 

 east Texas 34. E. compressa. 



35. Culms variable, somewhat to not at all compressed, 0.3-0.8 mm. thick; 



Edwards Plateau, Plains Country, s.e. Tex. and Okla 



35. E. acutisquamata. 



1. Eleocharis tuberculosa (Michx.) R. & S. Fig. 186. 



Tufted perennial, often with ascending rhizomes 3-6 mm. thick; culms 15-80 

 cm. long, compressed, 0.5-1 mm. thick in the longer dimension, erect, wiry, 

 sulcate, grayish-yellow; sheaths grayish-yellow, shortly oblique and acute; spikelets 

 ovoid to lance-ovoid, 5-15 mm. long, blunt to acute, with 25 to 40 flowers; scales 

 ovate to nearly orbicular, about 3 mm. long, blunt, grayish-yellow to stramineous, 

 firm (chartaceous to subcartilaginous), not keeled, marginally slightly thinner than 

 medially; bristles several, brownish, usually surpassing the achenial body; style 

 3-branched; achenial body broadly obovoid, 1.2-1.7 mm. long, obscurely trigo- 

 nous, stramineous to olivaceous, surficially with pronounced large cells (the cell- 

 walls prominent), lustrous; tubercle 1.2-1.7 mm. long, irregularly stele-shaped- 

 conic, apically rounded, toward the base flared out mushroomlike and as broad 

 as the body, very strongly truncate, the connection to the body very thin. 



Frequent in moist sand, wet meadows, about lakes and ponds, and along 

 streams, in s.e. and e. Tex., May-Nov.; coastal provinces and states, N.S. and 

 N.H. to Tex.; also Tenn. and Ark. 



2. Eleocharis Wolfii (Gray) Patt. 



Perennial (?); rhizomes slender, creeping, fragile; culms tufted, 2-edged, 

 somewhat concavo-convex or C-shaped in transection, 12-30 cm. long, 0.6-1.3 

 mm. broad, erect; sheaths apically scarious, oblique; spikelets ovoid-lanceolate, 

 acute, 5-10 mm. long, 18- to 34-flowered; scales narrowly ovate, acute, usually 

 with 2 purple longitudinal stripes and the rest stramineous, firm or marginally 

 scarious; bristles absent; style 3-branched; achenial bodies narrowly obovoid, 

 0.8-0.9 mm. long, pearly, obscurely trigonous to terete, with about 9 longitudinal 

 ridges and between each 2 ridges about 40 close horizontally elongate cells 

 (trabeculae) ; tubercle depressed-conic, about 0.1 mm. long, much narrower than 

 the body. 



Rare in wet sand and wet swales in prairies. Plains Country and s.e. Tex., 

 probably scattered elsewhere, spring-summer; Sask., Ind., 111., Mo., Kan., Colo., 

 (?) Okla., Tenn., La. and Tex. 



369 



