580 FLORA OF TEXAS. 



scales oblong, rigid, l-uerved ; nut obovate, as large as the 

 ovate compressed 3-angled tubercle; bristles rigid, hispid. 

 — Varies with larger spikes and pubescent bristles. (Scir- 

 pus tuberculosus, Michx.) Wet places, chiefly along the 

 coast. March-September. Culms 6-12' high ; spikes 

 3"-4" long (G"-8" in the var.). Nut shining. Peren- 

 nial. 



E. SIMPLEX, Torr. Culms unequally 3-sided, acute- 

 angled ; spikes short, ovate, acute ; scales ovate-oblong, 

 whitish, with brownish sides; nut obovate, flat on the 

 inner face, twice as long as the conical-beaked compressed 

 acute tubercle ; bristles rigid. (E. tortilis, Schult. ; Scirpus 

 simplex. Ell.) Miry places along streams. May-Septem- 

 ber. Culms l°-l-2-° high, very slender, twisted when dry ; 

 spikes 2"-3" long, angular, few-flowered. Perennial. 



E. MiCROFORMis, Buckley. Culms erect, setaceous, ces- 

 pitose, 1-2 inches high, smooth ; spikes ovate, obtuse or 

 subacute, 10-12-scaled ; scales ovate, acute or subobtuse, 

 reddish brown ; keel green ; achenia smooth, shining, pyri- 

 form, setae 6, equal to the seed in length. Mature achenia 

 black and shining, crowned with a broad white tuber- 

 cle, with a short j)oint in the centre. Northern Texas. 

 June. 



tt Culms terete or compressed, more or less spongy. 



E. OBTUSA, Schultes. Culms tufted, terete, thick and 

 spongy ; spikes ovate or oblong, obtuse, many-flowered ; 

 scales thin, oblong, obtuse, commonly brown on the sides, 

 green on the keel, wdth broad and wiiite margins ; st?/lo 

 2-3-cleft; nut (light brown) obovate, lenticular, smooth 

 and shining, scarcely wider than the short compressed 

 acute tubercle ; bristles 6, rigid, twice the length of the 

 nut. (Scirpus capitatus. Ell.) Muddy margins of ponds 

 and streams. Common. June-September. Culms G'-18' 

 high ; spikes 2"-4" long. 



