Eleocharis radicans |
Eleocharis melanocarpa |
|
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creeping spikerush, radical fiber optic spikerush, root spikerush |
black-fruit spike-rush, black-fruit spikesedge |
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Habit | Plants perennial, mat-forming; rhizomes 0.2–0.5 mm thick, longer internodes 5–10 mm, scales not evident. | |
Culms | obscurely to ca. 10-ribbed when dry, terete, 1–12 cm × 0.4–1 mm, very soft, spongy. |
to 2 times wider than thick, 35–60(–70) cm × 0.5–1.3 mm, hard, usually with to 10 blunt ribs, at 20X often finely ridged and minutely granular. |
Leaves | distal leaf sheaths fugaceous, colorless, translucent, apex blunt. |
distal leaf sheaths brown to reddish. |
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. |
3–12 × 3–4 mm; proximal scale amplexicaulous, 3.5–4 mm, midrib region very broad and fleshy, apex entire; subproximal scale with a flower; floral scales 30–40, 8–10 per mm of rachilla, orange-brown to stramineous, midrib region stramineous, broadly ovate, papery or sometimes membranous, 3–4 × 2 mm, apex entire, rounded. |
Flowers | perianth bristles equaling achene; anthers yellow to brown, 0.3–0.5 mm. |
perianth bristles present, sometimes rudimentary, brown, length variable, obscurely retrorsely spinulose; anthers brown, 1.7–2.2 mm. |
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. |
subdeltoid in outline, sometimes broadly obpyriform, equilaterally trigonous, angles prominent, 0.9–1.2 × 0.7–1.1 mm, apex truncate. |
Tubercles | brown, pyramidal, 0.15 × 0.15–0.2 mm. |
sessile, depressed-pyramidal, often apiculate, as wide as achene, 0.3–0.5 × 0.7–1.1 mm. |
Eleocharis radicans |
Eleocharis melanocarpa |
|
Phenology | Fruiting spring–winter (Apr–Dec). | Fruiting summer. |
Habitat | Stream alluvium, lake margins, meadows, seeps, bogs | Fresh, oligotrophic, acid, sandy or peaty, often drying shores, ponds, ditches |
Elevation | 100–1400 Ariz., Calif., Fla., La., Mich., Okla., Tex., Va. | 10–300 m (0–1000 ft) |
Distribution |
HI; n Mexico; West Indies; Central America (El Salvador); South America (Argentina, Chile)
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AL; FL; GA; IN; MA; MI; NC; NY; RI; SC; TX; VA
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Discussion | Eleocharis melanocarpa is reported from Rhode Island; I have not seen a voucher specimen. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 112. | FNA vol. 23, p. 89. |
Parent taxa | Cyperaceae > Eleocharis > subg. Scirpidium | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Melanocarpae |
Sibling taxa | ||
Synonyms | Scirpus radicans, E. acicularis var. radicans, E. lindheimeri | |
Name authority | (Poiret) Kunth: Enum. Pl. 2: 142. (1837) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 311. (1836) |
Web links |