558 CTPERACE.-E. (SF.DGE FAMILY.) 



of the perianth stont, downumvdlii harlifd, as long as the striated and pitted-rctic- 

 itldtcd triiinfjular aclienium arid its tubercle; culms tufted from fibrous roots, 

 about 1° hitjh. 



4. E. tuberculbsa, Ti. Br. Culms flattish, striate; spike 3" -6" long, 

 many-llowcivd ; tubcrdv Jhtttishatp-sh<ifi<d, as large as the bodi/ of the aclienium. 

 ■ — Wet sandy soil, Mass. along the coast to Virginia and southward. 



5. E. simplex, Torr. Culms sharplt/ triangular, capiilari/, twisting when 

 dry; s])ike 2" -3" long, fcw-flowercd ; conicul-beakcd tubercle much smal'er tJ.an 

 the achenium. (E. ttJrtilis, Schultcs.) — Eastern shore of Maryland (W. M. 

 Ca)ibi/), and southward. 



§3. Spike terete, much thicker than the culm, mnnij-fowrrcd ; the scales imbricated 

 in many or more than three ranks, tliin-membranactous or scarious in texture, with 

 a thicker midrib, usually brownish or purplish, sometimes deciduous at maturity. 

 (Eleogenus, Kees.) 



* Achenium smooth and lentictihir, and style 2-clef, or in No. G inore commonly 

 3-cli-/l : culms slender or thread form, terete or compressed. 



6. E. Obtusa, Schnltes. Culms nearly terete, tufted (8'- 14' high) from 

 fibrous roots ; spike globose-ovoid and with age oblung, obtuse, rarely becoming acute 

 (dull brown); the scales very obtuse and numerous (80- \30), densely crowded in 

 many ranks; style 3- (rarely 2-) clef; achenium bbovate, .shining, tumid- mar- 

 gined, about half the length of the 6-8 bristles, crowned with a short and very 

 broad fattened tubercle. — Muddy places : most common. 



7. E. Olivasea, Torr. Culms flattish, grooved, diffusely tufted on slender 

 matted rootstocks (2' -4' high) ; spike ovate, acutish, 20-30-fo>.cered ; scales ovale, 

 obtuse, rather loosely imbricated (puri)le with a green midrib and slightly scari- 

 ous margins) ; achenium obovate, dull, abruptly beaked with a narrow tubercle, 

 shorter than the 6-8 bristles. — Wet sandy soil, Mass. to New Jersey near the 

 coast, and soiitlnvard : also shore of Lake Ontario, J. A. Paine. 



8. E. pallistris, R. Br. Culms nearly terete, striate (l°-2° high), from 

 running rootstocks ; spike oblong-lanceolate, jyointed, many-flowered ; scales ovate- 

 oblong, loosely imbricated in several ranks, reddish-brown with a broad and 

 translucent whitish margin and a greenish keel, the upper acutish, the lowest 

 rounded and often enlarged; achenium obovate, somewhat shining, crowned 

 with a short ovate or ovate-triangular flattened tubercle, shorter than the usually 

 4 bristles. — Var. glatcescens (S. glauccscens, Willd. !) : culms slender or fili- 

 form ; tubercle narrower and acute, beak-like, sometimes half the length of the 

 achenium. — Var. c.Ilva (E. calva. Ton:): bristles wanting; tubercle short, 

 nearly as in the true E. palustris, but rather narrower (Watertown, New York, 

 Dr. Crawe). — Very common, either in water, when it is pretty stont and tall; 

 or in wet grassy grounds, when it is slender and lower. (Ku.) 



9. E. COmpressa, Sullivant. dims fit, striate, erect (l°-2° high); 

 sjnke orate-obhmg, or at length lanceolate, 20- .'50;/7o)rrm/ (4" -7" long) ; scales 

 lanceolate-ovate, acute, dark pnr])le with broad white pellucid margins and sum- 

 mit ; achenium olMvate -pear- shaped, compressed, crowned tvlth a small conical and 

 pointed tubercle; bristles I -4, very slender, fragile, shorter than or equalling the 

 achenium, sometimes none or a single rudiment.) — Wet places, N. New York 



