Eleocharis bolanderi
Eleocharis aestuum
Bolander's spikerush
tidal spikerush, tidal spikesedge
subterete, often with to 6 prominent ridges when dry, sulcate, 10–30 cm × 0.3–0.5 mm, firm to rigid, spongy.
often spreading or declining, 3–30 cm × 0.5–1 mm.
distal leaf sheaths persistent, not splitting, proximally brown, red, or stramineous, distally stramineous, green or reddish, papery, apex sometimes reddish, obtuse, rarely callose, tooth absent.
apex of distal leaf sheath obtuse, tooth to 0.2(–0.5) mm.
ovoid, 3–8 × 2–3 mm, apex acute to obtuse;
proximal scale amplexicaulous, entire;
subproximal scale with flower;
floral scales spreading in fruit, 8–30, 4–5 per mm of rachilla, dark brown to blackish, midrib regions often stramineous or greenish, ovate to lanceolate, 2–3 × 1.5 mm, apex entire, acute, often carinate in distal part of spikelet.
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.
perianth bristles 3–6, whitish to stramineous, stout to slender, often unequal, from rudimentary to 1/2 of achene length;
stamens 3;
anthers dark yellow to brown, 0.9–1.4 mm;
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.
falling with scales, stramineous, rarely dark brown, ovoid to obpyriform, slightly to greatly compressed-trigonous, rarely thickly lenticular, angles prominent or abaxial angle obscure, 0.9–1.2 × 0.65–0.8 mm, apex narrowly to broadly truncate, neck short, often compressed more than body, at 20–30X finely rugulose with more than 20 horizontal ridges in a vertical series or reticulate or cancellate.
0.75–1 × 0.6–0.8 mm.
whitish to brown, pyramidal, lower than wide, often 3-lobed as viewed from the top, 0.1–0.3 × 0.4–0.65 mm.
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.
Eleocharis bolanderi
Eleocharis aestuum
Eleocharis bolanderi is clearly distinct from E. montevidensis, from which it differs in its dense, tufted habit with short, caudexlike rhizomes, its leaf sheaths without a tooth, its achene and tubercle shapes, and its acute floral scales.
Specimens of Eleocharis bolanderi without rhizomes or achenes are easily confused with E. decumbens, which often may be distinguished by culms 0.5–2 mm wide, and spikelets with scales sometimes more than 3 mm long. The tubercles of E. bolanderi are usually poorly developed and much lower than wide; in E. decumbens they are usually well developed and about as high as wide.
(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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