576 CYPERACE^E. (SEDGE FAMILY.) 



15. E. COmpressa, Sullivant. Culms fat, striate, tufted, erect (1--2* 

 high); spikelet ovate-oblong, or at length lanceolate, 20 - 30-Jioicere d (4-7'' 

 loiig) ; scales lanceolate-ovate, acute, dark purple with broad white pellucid 

 margins and summit ; achene yellowish, obovate-pear-shaped, obtusely triangu- 

 lar, wrinkled, crowned with a small conical and pointed tubercle ; bristles 1-4, 

 very slender, fragile, shorter than or equalling the achene (sometimes none or 

 a single rudiment). Wet places, N. Y. and Out. to Minn, and Mo. 



16. E. melanoearpa, Torr. Culms flattened, grooved, wiry, erect (9- 

 18' high) ; spikelet cylindrical-ovoid or oblong, thick, obtuse, densely many-flow- 

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

 brownish with broad scarious margins ; achene smooth, obovate-top-shaped , ob- 

 ttiKc/y triangular, the broad summit entirely covered like a lid by the Jidt de-pressed 

 tubercle, which is raised in the centre into a short abrupt triangular point ; 

 bristles often obsolete; achene soon blackish. Wet sand, Mass, to Fla. 



17. E. tricostata, Torr. Culms Jiattish (1 -2 high) ; spikelet soon cylin- 

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

 rusty brown, with broad scarious margins ; achene obovate, with 3 prominent 

 thickened angles, minutely rough-wrinkled, crowned with a short-conical acute 

 tiibi-rclr ; bristles none. N. J. to Fla. 



18. E. W61fli, Gray. Culms slender (1 high), from very small creeping 

 rhi/.nmes, "2-edi/cd ; spikelet ovate-oblong, acute ; scales ovate-oblong, obtuse, 

 scarious, pale purple ; acheue pyriform, shining, with 9 nearly equidistant obtuse 

 ribfi mill transverse wrinkles between them; tubercle depressed, truncate, more or 

 less apiculate ; bristles not seen. Wet prairies, N. Iowa and S. Minn. 



4. Spikelet more or less flattened , thicker than the slender or capillary culm, 

 fi ic man>i-flowered ; the thin membranaceous scales somewhat 2 3-ranked ; 

 style 3-cleft ; bristles of the perianth 3 - 6, fragile or fugacious. Small or del- 

 icate species, differing from the last division c/iiejly in the Jiattish spikelets. 



* Tubercle contracted at its junction with the achene. 



19. E. acicularis, R. Br. Culms finely capillary (2-8' long), more or 

 less 4-atii/ii/nr ; spikelet 3-9-flowered; scales ovate-oblong, rather obtuse 

 (greenish with purple sides) ; achene obovate-oblong, with 3-ribbed angles and 

 2-3 times as many smaller intermediate ribs, also transversely striate, longer 

 than the 3-4 very fugacious bristles; tubercle conical-triangular. Muddy 

 shores, across tin 1 continent. (Eu., Asia.) 



20. E. pygmsea, Torr. Culms bristle like, flattened and grooved (1 - 2' 

 high) ; spikelet ovate, 3 - 8-flowered ; scales ovate (greenish), the upper rather 

 acute; achene ovoid, acutely triangular, smooth and shining, tipped ivith a mi- 

 nute tubercle; bristles mostly longer than the fruit, sometimes wanting. 

 lirackish marshes, from N. Brunswick to Fla. 



* * Tubercle continuous with the nutlet and not contracted at base. 



21 . E. pauciflora, Link. Culms striate-angled, very slender (3 - 9' high), 

 scarcely tufted, on slender running rootstocks, with a short truncate sheath at 

 base ; scales of the ovate spikelet evidently 2-ranked, chestnut-brown, pointless, 

 all flower-bearing, the two lower larger ; bristles 3-6, about as long as the 

 conspicuously beaked triangular achene. (Scirpus pauciflorus, Liijlitfuot.) 

 Wet places, N. Y. to N. 111. and Minn., north and westward. (Eu., Asia.) 



