Difference between revisions of "Eleocharis nigrescens"

(Nees) Steudel

Syn. Pl. Glumac. 2: 77. 1854.

Basionym: Scirpidium nigrescens Nees
Treatment appears in FNA Volume 23. Treatment on page 93. Mentioned on page 70, 91.
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|distribution=Fla.;S.C.;Mexico;West Indies;Bermuda;South America;Africa.
 
|distribution=Fla.;S.C.;Mexico;West Indies;Bermuda;South America;Africa.
 
|discussion=<p>Usually all the floral scales fall from the rachilla at maturity. The achene epidermis is usually translucent, revealing the brown color of the enclosed seed.</p><!--
 
|discussion=<p>Usually all the floral scales fall from the rachilla at maturity. The achene epidermis is usually translucent, revealing the brown color of the enclosed seed.</p><!--
--><p>Clarification of delimitation of Eleocharis microlepis (Grisebach) D. A. Simpson, E. setifolia, (A. Richard) A. Raynal, and E. nigrescens in the Americas requires further investigation (D. A. Simpson 1988). Specimens from North America treated herein as E. nigrescens seem to agree well with Simpson’s illustration of E. nigrescens; the anther length of 0.2–0.3 mm recorded here is closer to that of E. microlepis. Simpson (pers. comm.) has not examined specimens of either E. nigrescens or E. microlepis from North America, and lists both E. microlepis and E. setifolia from the West Indies and only E. setifolia from South America.</p>
+
--><p>Clarification of delimitation of <i>Eleocharis</i> microlepis (Grisebach) D. A. Simpson, <i>E. setifolia</i>, (A. Richard) A. Raynal, and <i>E. nigrescens</i> in the Americas requires further investigation (D. A. Simpson 1988). Specimens from North America treated herein as <i>E. nigrescens</i> seem to agree well with Simpson’s illustration of <i>E. nigrescens</i>; the anther length of 0.2–0.3 mm recorded here is closer to that of E. microlepis. Simpson (pers. comm.) has not examined specimens of either <i>E. nigrescens</i> or E. microlepis from North America, and lists both E. microlepis and <i>E. setifolia</i> from the West Indies and only <i>E. setifolia</i> from South America.</p>
 
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|publication year=1854
 
|publication year=1854
 
|special status=
 
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|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/9216fc802291cd3df363fd52122300479582ede7/coarse_grained_fna_xml/V23/V23_132.xml
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|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/8f726806613d60c220dc4493de13607dd3150896/coarse_grained_fna_xml/V23/V23_132.xml
 
|genus=Eleocharis
 
|genus=Eleocharis
 
|subgenus=Eleocharis subg. Eleocharis
 
|subgenus=Eleocharis subg. Eleocharis

Revision as of 16:05, 18 September 2019

Plants usually annual, tufted, not stoloniferous; rhizomes absent. Culms sometimes ascending, subterete, elliptic, or polygonal, (1–)3–7.5(–9) cm × 0.2–0.5 mm, very soft. Leaves: distal leaf sheaths persistent or disintegrating, colorless, stramineous or green, spotted red-brown to purple, membranous, apex narrowly acute. Spikelets: basal spikelets absent; never proliferous, ovoid or ellipsoid, terete, 2–4.7(–8.5) × 1–2 mm, apex acute to blunt; proximal scale empty or with flower, persistent, clasping 1/2 of culm, similar to floral scales (but 1.1–1.7 mm, midrib region broadly green); subproximal scale with a flower; floral scales spiraled, 10–30(–100), 10–16 per mm of rachilla, colorless, whitish, or pale brown, mottled red-brown to purple, midribs pale brown or green, ovate or elliptic, 1–1.2 × 0.45–0.6 mm, membranous, midrib prominent, apex rounded. Flowers: perianth absent; stamens 1; anthers 0.2–0.3 mm; styles 3-fid. Achenes colorless (appearing green-brown from enclosed seed) or whitish, sometimes spotted red-brown, obovoid, trigonous, angles prominent, 0.5–0.6 × 0.33–0.4 mm, apex constricted proximal to tubercle, smooth. Tubercles white, gray or pale brown, pyramidal or umbonate, trigonous, 0.1–0.15 × 0.15–0.2 mm.


Phenology: Fruiting summer–winter.
Habitat: Moist terrestrial sites such as sandy and peaty soils on pond margins, ditches, pine flatwoods
Elevation: 0–30 m

Distribution

V23 132-distribution-map.jpg

Fla., S.C., Mexico, West Indies, Bermuda, South America, Africa.

Discussion

Usually all the floral scales fall from the rachilla at maturity. The achene epidermis is usually translucent, revealing the brown color of the enclosed seed.

Clarification of delimitation of Eleocharis microlepis (Grisebach) D. A. Simpson, E. setifolia, (A. Richard) A. Raynal, and E. nigrescens in the Americas requires further investigation (D. A. Simpson 1988). Specimens from North America treated herein as E. nigrescens seem to agree well with Simpson’s illustration of E. nigrescens; the anther length of 0.2–0.3 mm recorded here is closer to that of E. microlepis. Simpson (pers. comm.) has not examined specimens of either E. nigrescens or E. microlepis from North America, and lists both E. microlepis and E. setifolia from the West Indies and only E. setifolia from South America.

Selected References

None.

Lower Taxa

None.
... more about "Eleocharis nigrescens"
Jeremy J. Bruhl +  and S. Galen Smith +
(Nees) Steudel +
Scirpidium nigrescens +
Fla. +, S.C. +, Mexico +, West Indies +, Bermuda +, South America +  and Africa. +
0–30 m +
Moist terrestrial sites such as sandy and peaty soils on pond margins, ditches, pine flatwoods +
Fruiting summer–winter. +
Syn. Pl. Glumac. +
Eleocharis +
Eleocharis nigrescens +
Eleocharis (sect. Eleocharis) ser. Tenuissimae +
species +