Eleocharis microcarpa |
Eleocharis aestuum |
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small-fruit spikesedge, smallfruit spikerush |
tidal spikerush, tidal spikesedge |
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Habit | Plants usually annual, tufted, sometimes mat-forming via proliferating and arching inflorescences (stoloniferous), sometimes entirely vegetative; rhizomes absent. | |||||
Culms | often ascending or arching, quadrangular or broadly elliptic, 2–40 cm × 0.1–0.4(–0.6) mm, soft. |
often spreading or declining, 3–30 cm × 0.5–1 mm. |
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Leaves | distal leaf sheaths persistent or disintegrating, pale brown, green or red-brown, streaked or mottled red-brown or purple, translucent, membranous, apex narrowly acute. |
apex of distal leaf sheath obtuse, tooth to 0.2(–0.5) mm. |
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Spikelets | basal spikelets absent; often proliferous, ovoid to ellipsoid or lanceoloid, terete, 2–10.7 × 1–2 mm, apex acute; proximal scale empty, persistent, amplexicaulous, dissimilar to floral scales, often longer, often resembling an involucral bract, ovate to lanceolate, midrib markedly thickened and broad and often prolonged beyond lamina; subproximal scale with flower; floral scales spiraled, colorless, whitish, or pale brown, streaked or mottled red-brown or purple, midribs green and red-brown or green and purple, ovate to elliptic, 0.8–1.5 × 0.4–0.8 mm, membranous, midrib obscure to prominent. |
ellipsoid to ovoid, 3–10 × 2–4 mm, apex blunt to subacute; floral scales 10–100+, 10 per mm of rachilla, colorless to pale brownish except for green midrib, 1.5–2 × 1 mm, midribs not keeled, apex rounded. |
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Flowers | perianth bristles present or sometimes apparently absent; stamens 3; anthers 0.15–0.35; styles 3-fid. |
perianth bristles absent or 2–4, stramineous or whitish, shorter than to nearly 1/2 achene, very slender, without spinules; stamens 2(–3); anthers 0.3–0.5 mm; styles 2-fid or some 3-fid. |
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Achenes | whitish to olive or pale brown, sometimes spotted olive or red-brown, obovoid, trigonous (or subterete), angles prominent, 0.55–0.8 × 0.3–0.5 mm, apex constricted proximal to tubercle, smooth. |
0.75–1 × 0.6–0.8 mm. |
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Tubercles | green or pale brown to red-brown, trigonous. |
deltoid, 0.2–0.3 × 0.35–0.45(–0.55) mm, 1/2–3/4as high as wide, 1/4–1/3 as high and 1/2–2/3(–4/5) as wide as achene. |
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Eleocharis microcarpa |
Eleocharis aestuum |
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Phenology | Fruiting summer–fall (Jul–Oct). | |||||
Habitat | Fresh tidal river shores | |||||
Elevation | 0–10 m (0–0 ft) | |||||
Distribution |
AL; FL; GA; IN; LA; MA; MD; MI; MS; NC; NJ; PA; SC; TN; TX; VA; West Indies
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CT; DE; MA; ME; NJ; NY; PA |
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Discussion | Varieties 2 (2 in the flora). Specimens of Eleocharis brittonii and E. microcarpa without achenes are often difficult to distinguish. More detailed study of the four apparent entities across the two species is warranted. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eleocharis aestuum is very similar to E. diandra and E. ovata; E. diandra differs from E. aestuum in its lower tubercles, brown floral scales, and absence of perianth bristles; E. ovata differs as given in the key to species. D. M. Hines (1975) described E. aestuum using the epithet “palidostachys” [ined.]. Specimens from shores of the Lake-of-the-Woods in Minnesota, and a reservoir and farm in Hardin and Fayette counties, Tennessee, may be referable to E. aestuum. The only recent records of E. aestuum are from the Androscoggin and Kennebec rivers in Maine and the Hudson River in New York (A. Haines 2001). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 23, p. 95. | FNA vol. 23, p. 104. | ||||
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Ovatae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 312. (1836) | Hines ex A. Haines: Novon 11: 45. (2001) | ||||
Web links |