ctpekacejE. (skdge family.) 553 



to Ohio and Illinois. — Culms tufted on running rootstocks, strikingly flat, 

 often spirally twisted in drying. 



* * Achenlum triangular or turcjid : sti//e S-chp. 

 t- Bristles cqttalliuj or sur/)ussiii(j thi smooth ucheniiim, doivnivurd ij barbed, persistent. 



10. E. rostellata, Torr. Cidms flattened and striatt-grooucd, wiry, erect 

 (l°-2|^-° liigli), lite sterile ones reclining, rootini; and jiroiiferoiis from the apex 

 (l'^-'2° high), the sheath transversely truncate; spike s/iindle-shaped, 12-20- 

 flowcrcd ; scales ovate, obtuse (light-brown); achenium obovate-triangular, 

 narrowed into the confluent pyramidal tubercle, which is overtopped by the 

 4-6 bristles. —Marshes, Ehode Island [OIney), E. Massachusetts ( W. Boott), 

 and Vermont {Tnrb-nnan) to New Jersey (Dr. Allen), Alexandria, Virginia (A. 

 IT. Cnrtiss), Michigan and southward. 



11. E. intermedia, Sclmltes. Culms capillary, iviry, striate-grooved, 

 densely tufted from fibrous roots, diffusely spreading or reclining (6' -12' long) ; 

 spike oblong-ovate, aciitish, loosely \0 - 20-floivered (2" -3" long); scales oblong, 

 obtuse, green-keeled, the sides purplish-brown ; achenium obovoid with a nar- 

 rowed base, beaked with a slender conical-awl-shaped distinct tubercle, which 

 nearly equals the 6 bristles. (E. reclinata, Kuntli.!) — Wet slopes: conmion 

 from New York and Penn. to Illinois and northward. 



12. E. mieroearpa, Torr., var. filiculmis, Torr. Like the preceding, 

 but more capillary ami heads smaller (lj"-2" \o\\g), sometimes proliferous, the 

 one or more short new culms from the axil of its lowest scale, which persists 

 as an herbaceous bract ; achenium very much smaller, witli sharper angles and a 

 short conical tubercle, which is hardly equalled by the 3-6 slender bristles. — 

 Wet pine barrens, New Jersey and southward. 



-t- -1- Bristlea 2-4, slwrter than the achenium, slender and fragile, or none. 



13. E. tenuis, Sclmltes. Culms almost capillary, erect from running root- 

 stocks, 4-angular and tlattish (1° high), the sides concave; spilce elliptical, acut- 

 ish, 20- 30-flowered {3" long) ; scales ovate, oi/ifsf, chestnut-purple with a broad 

 scarious margin and green keel ; achenium oborate, roughish-wrinkled, crowned with 

 a small depressed tubercle, persistent after the fall of the scales; bristles half the 

 length of the achenium, or wanting. (E. elliptiea, Kunth.!) — Wet meadows 

 and bogs: common, early-flowering; June. 



14. E. melanocarpa, Torr. Culms flattened, grooved, wiry, erect (9'- 

 18' high); spike rylindrical-oroid or oblong, thick, obtuse, densely many-flowered 

 (■3" -6" long) ; scales closely many-ranked, roundish-ovate, very obtuse, brown- 

 ish with broad scarious margins ; achenium smooth, ohovate-top-shaped, obtusely 

 triangular, the broad .lumna't entirely covered like a lid by the flat depressed tubercle, 

 which is raised in the centre into a short abrupt triangular point ; bristles shorter 

 than the (soon blackish) achenium, often obsolete. — Wet sand, Plymouth, 

 Massacbusctrs, to Virginia, and southward along the const. 



1.5. E. tricOStata, Torr. Culms flatfish (10-2° liij;h) ; spike soo:i cyfin- 

 driral, densely many-flowered (6" -9" long, thickish ; scales ovate, very obtuse, 

 rusty brown, witii broad scarious margins; achenium oborate. ivith 3 promi-nent 

 thickened (tngUs, minnttly rom/h-wrinkled, cronmeA with a short -conical acuti' tubercle; 

 bristles none. — Quaker Bridge, New Jersey (Knieskern), and southward. 



