Eleocharis radicans |
Eleocharis bifida |
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creeping spikerush, radical fiber optic spikerush, root spikerush |
glades spikerush |
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Habit | Plants perennial, mat-forming; rhizomes 0.2–0.5 mm thick, longer internodes 5–10 mm, scales not evident. | Plants perennial, densely cespitose; rhizomes concealed by persistent culm bases, short, 4–5 mm thick, hard, cortex persistent, internodes crowded, scales decaying to coarse fibers, 1 cm, papery. |
Culms | obscurely to ca. 10-ribbed when dry, terete, 1–12 cm × 0.4–1 mm, very soft, spongy. |
greatly compressed, 4–10 times wider than thick, often with 1 or 2 sharp ridges on 1 side, (8–)20–35 cm × 0.7–2.3 mm, hard, finely striate, spongy. |
Leaves | distal leaf sheaths fugaceous, colorless, translucent, apex blunt. |
distal leaf sheaths persistent, not splitting, proximally red or stramineous, distally green to stramineous, inflated, papery, apex dark brown, broadly obtuse to subtruncate, callose, tooth absent. |
Spikelets | ovoid, 2–3 × 1–1.5 mm, apex acute; scales 5–15, 5–7 per mm of rachilla, colorless to stramineous, rarely slightly reddish, medially broadly greenish to colorless, faintly 3–5-veined, often ovate, membranous, fleshy; proximal scale 2–2.5 × 0.7 mm, other scales 1.5–2 × 0.7 mm, midrib obscure to slightly keeled, apex acute to rounded. |
ovoid, 4–9 × 2.5–4 mm, apex acute; proximal scale clasping 2/3–3/4 of culm, apex 2-fid; subproximal scale empty or with a flower; floral scales spreading in fruit, 30–60, 6–9 per mm of rachilla, medium or pale brown, midrib region often paler, ovate-lanceolate, 2.5–3.5 × 1.5 mm, apex 2-fid, carinate in distal part of spikelet. |
Flowers | perianth bristles equaling achene; anthers yellow to brown, 0.3–0.5 mm. |
perianth bristles 0(–5), stramineous to pale brown, 1/2 of to equaling achene length; stamens 3; anthers orange-brown, 0.7–1.5 mm; styles 3-fid. |
Achenes | brownish, angles plus longitudinal ridges ca. 7, narrowly obovoid, 2 times longer than wide, 0.75–0.9 × 0.35–0.4 mm, trabeculae ca. 50, distinct. |
falling with scales, yellow-brown to medium brown, obovoid to obpyriform, nearly equilaterally trigonous, cross section circular to slightly compressed, angles obscure or evident, 0.9–1.1 × 0.6–0.75, neck usually very short, finely rugulose at 10–30X, 20 or more low, blunt horizontal ridges in vertical series. |
Tubercles | brown, pyramidal, 0.15 × 0.15–0.2 mm. |
brown, depressed-pyramidal, often rudimentary, 0.1–0.25 × 0.2–0.3 mm. |
Eleocharis radicans |
Eleocharis bifida |
|
Phenology | Fruiting spring–winter (Apr–Dec). | Fruiting spring–summer (May–Jun). |
Habitat | Stream alluvium, lake margins, meadows, seeps, bogs | Seasonally wet places on limestone, cedar (juniper) glades, stream beds, prairies, ditches |
Elevation | 100–1400 Ariz., Calif., Fla., La., Mich., Okla., Tex., Va. | 200–300 m (700–1000 ft) |
Distribution |
HI; n Mexico; West Indies; Central America (El Salvador); South America (Argentina, Chile)
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AL; GA; KY; TN |
Discussion | Eleocharis bifida was previously included in E. compressa. A very few specimens of E. compressa var. compressa from the states where E. bifida is known are like E. bifida except for their entire proximal floral scales and evident rhizomes. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 112. | FNA vol. 23, p. 85. |
Parent taxa | Cyperaceae > Eleocharis > subg. Scirpidium | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Synonyms | Scirpus radicans, E. acicularis var. radicans, E. lindheimeri | |
Name authority | (Poiret) Kunth: Enum. Pl. 2: 142. (1837) | S. G. Smith: Novon 11: 243, figs. 1F–J, 2. (2001) |
Web links |