Eleocharis nitida Fernald

Eleocharis nitida is much like E. elliptica but all structures are smaller; intermediates are unknown.

Plants perennial, mat-forming; rhizomes evident, 0.3–0.5 mm thick, hard, cortex persistent, longer internodes 2 mm, scales persistent or fugaceous, 2–3 mm, membranous to papery, slightly fibrous. Culms terete, 2–15 cm × 0.15–0.3 mm, firm to soft. Leaves: distal leaf sheaths persistent, not splitting, proximally stramineous to reddish, distally green or stramineous to reddish, membranous, apex often red, obtuse to acute, tooth absent. Spikelets ovoid, 1–4 × 1–2 mm, obtuse to acute; proximal scale amplexicaulous, apex entire; subproximal scale with flower; floral scales spreading in fruit, 5–30, 8 per mm of rachilla, medium to very dark brown, midrib region often pale or greenish, broadly ovate, 1–1.3 × 1 mm, apex rounded, entire, not carinate. Flowers: perianth bristles absent; stamens 3; anthers yellow, 0.3 mm; styles 3-fid. Achenes persistent after scales fall, to dark yellow-orange or brown, broadly obpyriform, trigonous, angles evident, 0.6–0.65 × 0.5–0.55 mm, rugulose at 20–30X, 20 blunt horizontal ridges in each vertical series. Tubercles brown, greatly depressed, rudimentary, 0.05–15 × 0.15–0.3 mm.

Nfld. and Labr., N.S., Ont., Que., Sask.; Alaska, Mich., Minn., N.H., Wis.

Fruiting late spring (Jun)–summer.

Fresh bog pools, streams, disturbed places; 30–400m.

Eleocharis nitida Fernald, Rhodora 8: 129. 1906
Perennial from a slender rootstock; culms capillary, 4-angled, striate, 2-8 cm. high; apex of the upper sheath slightly inflated, whitish; spikelet oblong-ovoid, somewhat acute, 2.5-4.5 mm. long, 1.5-2.5 mm. thick, 8-20-flowered ; scales elliptic-oblong, with rounded tips, purplish-brown, with greenish ribs and very narrow scarious margins, the lowermost larger : achene golden-yellow when mature, narrowly obovoid, sharply trigonous, 0.7-1 mm. long, the roughened surface and depressed tubercle as in E. elliptica.
Type locality: Springy place, Parker's Station, Pontiac County, Quebec (Macoun).
Distribution: Moist places, chiefly in acid peat: Newfoundland, Quebec, Ontario (Ottawa), Nova Scotia, New Hampshire, Wisconsin, Minnesota, British Columbia (Glacier Lake, herb. Univ. Minnesota) ; Kodiak Island, Alaska.

Eleocharis nitida is a species of flowering plant commonly called neat spikerush, it is a member of the sedge family Cyperaceae.

Eleocharis nitida là loài thực vật có hoa trong họ Cói. Loài này được Fernald mô tả khoa học đầu tiên năm 1906.