Eleocharis cellulosa |
Eleocharis diandra |
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Gulf Coast spikerush, Gulfcoast spikesedge |
Wright's spikerush, Wright's spikesedge |
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Habit | Plants perennial; rhizomes 1–4 mm thick, soft to hard, longer internodes 3–7.5 cm, scales 5 mm, tubers absent. | |
Culms | terete or obtusely trigonous, 30–80 cm × 1–5 mm, soft to hard, not septate-nodulose, internally spongy, transverse septa incomplete; plants never forming filiform, flaccid culms. |
often spreading or reclining, 2–25 cm × 0.3–1 mm. |
Leaves | distal leaf sheaths persistent, membranous, apex acute to acuminate, often prolonged into a slender awn to 4 mm. |
apex of distal leaf sheath acute to acuminate, tooth sometimes present, to 0.2 mm. |
Spikelets | not proliferous, 14–54 × 3–5.6 mm; rachilla joints without winglike remnants of floral scales; proximal scale empty, amplexicaulous, 2.5–4.9 mm; floral scales 40–180, 2–3 per mm of rachilla, stramineous to pale brown, flanks sometimes minutely dotted reddish, usually with pale to dark brown, reddish, or purplish submarginal band, obovate to suborbicular, widest in middle, 3.4–4.5(–6) × 3–4.8 mm, cartilaginous, membranous toward margins, margins broadly translucent, membranous, apex rounded. |
ovoid, 2–7 × 1–4 mm, apex subacute; proximal scale either with flower or empty, base encircling 1/2 of culm; floral scales 50–100, 10 per mm of rachilla, orange to purple-brown, ovate, 1–1.5 × 0.8 mm, midrib slightly keeled, apex rounded to acute. |
Flowers | perianth bristles 6–7, medium brown to pale brown or reddish, slender, proximally slightly flattened, subequal to unequal, mostly exceeding achene, 2–3.4 mm, smooth or sometimes finely retrorsely spinulose; anthers reddish brown, 1.7–2.5 mm; styles 3-fid. |
perianth bristles absent; stamens 2(–3); anthers yellow, 0.2–0.3 mm; styles 2-fid or some 3-fid. |
Achenes | brown, biconvex, obpyriform, 2.2–2.8 × 1.3–1.9 mm, markedly sculptured at 10–15X, each face with (17–)20–24 rows of isodiametric to slightly transversely elongated cells, apex narrowed to a stout, often pale, spongy region 0.8–1.1 mm wide at base, 1/2–3/4 of achene width. |
0.7–1 × 0.6–0.9 mm. |
Tubercles | dark brown, lamelliform to pyramidal, 0.1–0.5 × 0.2–0.5 mm. |
deltoid 0.1–0.2 × 0.25–0.45 mm, 1/3–1/2 as high as wide, 1/8–1/4 as high and 3/4–9/10 as wide as achene. |
Eleocharis cellulosa |
Eleocharis diandra |
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Phenology | Fruiting late spring–winter. | Fruiting late summer–fall. |
Habitat | Brackish to saline marshes, shores, ditches, mostly coastal, often abundant or dominant | Fresh, mostly sandy, shores of large lakes and streams, sometimes slightly tidal |
Elevation | 0 (Florida)–600 (Arkansas, Texas) m (0 (Florida)–2000 (Arkansas, Texas) ft) | 0–100 m (0–300 ft) |
Distribution |
AL; AR; FL; GA; MS; NC; SC; TX; Mexico; West Indies; Central America (Nicaragua)
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CT; MA; NH; NY; VT; ON
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Discussion | Of conservation concern. Eleocharis diandra is close to E. ovata and E. aestuum; it probably should be treated as a distinct species (A. Haines 2001). It is apparently adapted to the greatly fluctuating water levels of rivers and large lakes (e.g., Oneida Lake in New York, Lake Champlain in Vermont). I have not seen specimens of E. diandra from Maine, New Jersey, or Pennsylvania, which may be based on specimens of E. aestuum. Specimens from the Lake-of-the-Woods shore in southwest Ontario are like E. diandra; they have floral scales with apices rounded, not acute as in typical E. diandra. The only recent observations of E. diandra are from the Connecticut River in Massachusetts (1985) and Oneida Lake in New York (1968; A. Haines 2001). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 118. | FNA vol. 23, p. 103. |
Parent taxa | Cyperaceae > Eleocharis > subg. Limnochloa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Ovatae |
Sibling taxa | ||
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 298. (1836) | C. Wright: Bull. Torrey Bot. Club 10: 101. (1883) |
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