View source for Eleocharis subg. Scirpidium

{{Treatment/ID
|accepted_name=Eleocharis subg. Scirpidium
|accepted_authority=(Nees) Kukkonen
|publications={{Treatment/Publication
|title=Ann. Bot. Fenn.
|place=27: 114. 1990
|year=1990
}}
|basionyms={{Treatment/ID/Basionym
|name=Undefined subg. Scirpidium
|authority=Nees
|rank=subgenus
|publication_title=Linnaea
|publication_place=9: 293. 1834
}}
|synonyms={{Treatment/ID/Synonym
|name=Eleocharis (sect. Undefined) ser. Aciculares
|authority=(C. B. Clarke) Svenson
|rank=series
}}
|hierarchy=Cyperaceae;Eleocharis;Eleocharis subg. Scirpidium
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Cyperaceae]]</div><div class="higher-taxon"><small>genus</small>[[Eleocharis]]</div><div class="higher-taxon"><small>subgenus</small>[[Eleocharis subg. Scirpidium]]</div></div>
|volume=Volume 23
|mention_page=
|treatment_page=
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>annual or perennial, very rarely with spikelets proliferating, culms never rooting at tips (spikelets very rarely proliferating in <i>Eleocharis reverchonii</i>). <b>Rhizomes</b> present or absent, creeping. <b>Tubers</b> and bulbs (resting buds) absent, or resting buds sometimes present in <i>E. acicularis</i>. <b>Culms</b> 1–40 cm × 0.2–1.2 mm, spongy, transverse septa incomplete. <b>Spikelets</b> ovoid to subcylindric, terete, much wider than their culms, 2–9 mm; rachilla with proximal internodes as long and as thick as internodes in middle of spikelet; proximal scale subtending a flower; floral scales ca. 4–30 per spikelet, spiraled, 1–3.5 mm, with 1 vein or fewer than 10 widely spaced longitudinal veins, membranous. <b>Styles</b> 3-fid. <b>Achenes</b> trigonous to nearly terete, 0.5–1.1 mm, with 9–13 longitudinal rows of fine horizontal ridges (trabeculae) between much more prominent longitudinal ridges and achene angles. <b>Tubercles</b> distinct from achene in color, texture and form, not dorsoventrally greatly compressed.</span><!--

-->{{Treatment/Body
|distribution=North America to South America;West Indies;Eurasia;Hawaii;Australia (probably introduced).
|discussion=<p>Species ca. 12 (7 in the flora).</p><!--
--><p>The three achene angles are very similar to the longitudinal ridges. Plants of subg. Scirpidium without achenes are easily mistaken for plants of 8a3. <i>Eleocharis </i>subg.<i> Eleocharis</i> sect. Parvulae, which may be distinguished by the absence of a flower in the axil of the proximal scale of the spikelet.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  <h3 class="treatment-key-header" id="key-0">Key to the species of Eleocharis subg. Scirpidium</h3>
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Culms distinctly compressed, to 1.2 mm wide, each side with 1 to few sharp ridges or 1 side smooth, margins usually––and ridges often––minutely serrulate at 10–30X; spikelet scales (2.2–)2.7–3.2 mm.
|[[Eleocharis wolfii|Eleocharis wolfii]]
|-id=key-0-1
|1
|Culms not or slightly compressed, or if distinctly compressed then each side with 3–6 blunt ridges, to 0.5(–0.7) mm wide, margins and ridges smooth; spikelet scales 0.8–2.5(–3.5) mm.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Floral scales 0.8–2 mm, apex narrowly acute to acuminate, mostly slightly recurved; anthers 0.2–0.5 mm; culms 1–7 cm, mostly densely tufted; rhizomes seldom evident.
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Floral scales 1.5–2.5 mm, apex rounded to acute, not recurved; anthers 0.3–1.5 mm; culms 1–45 cm; rhizomes mostly evident.
|[[#key-0-5| > 5]]
|-id=key-0-3
|3
|Achenes 0.4 mm, obpyriform; anthers 0.7–1.2 mm; floral scales lanceolate, folded lengthwise.
|[[Eleocharis brachycarpa|Eleocharis brachycarpa]]
|-id=key-0-3
|3
|Achenes 0.5–0.75 mm, obovoid, rarely obpyriform; anthers 0.2–0.5 mm; floral scales ovate to lanceolate, not folded lengthwise.
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Achenes broadly obovoid to obpyriform, 0.5–0.6 mm, trabeculae 15–20; anthers 0.2–0.3 mm.
|[[Eleocharis cancellata|Eleocharis cancellata]]
|-id=key-0-4
|4
|Achenes obovoid, (0.55–)0.65–0.75 mm, trabeculae 20–30; anthers (0.2–)0.3– 0.5 mm.
|[[Eleocharis bella|Eleocharis bella]]
|-id=key-0-5
|5
|Anthers 0.3–0.5 mm; culms very spongy, without prominent ridges or angles, 1–12 cm.
|[[Eleocharis radicans|Eleocharis radicans]]
|-id=key-0-5
|5
|Anthers 0.5–1.5 mm; culms firm to flaccid, not very spongy, often prominently ridged or angled, 1–45 cm.
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Achenes 0.5–0.7 mm, trabeculae 20–30; scales 1.5–1.7 mm; culms 0.15–0.3 mm wide.
|[[Eleocharis reverchonii|Eleocharis reverchonii]]
|-id=key-0-6
|6
|Achenes 0.7–1.1 mm, trabeculae 30–60; scales 1.5–2.5(–3.5) mm; culms 0.2– 0.5(–0.7) mm wide.
|[[Eleocharis acicularis|Eleocharis acicularis]]
|}
</div></div><!--

-->{{#Taxon:
name=Eleocharis subg. Scirpidium
|authority=(Nees) Kukkonen
|rank=subgenus
|parent rank=genus
|synonyms=Eleocharis (sect. Undefined) ser. Aciculares
|basionyms=Undefined subg. Scirpidium
|family=Cyperaceae
|distribution=North America to South America;West Indies;Eurasia;Hawaii;Australia (probably introduced).
|reference=None
|publication title=Ann. Bot. Fenn.
|publication year=1990
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V23/V23_163.xml
|genus=Eleocharis
|subgenus=Eleocharis subg. Scirpidium
}}<!--

-->[[Category:Treatment]][[Category:Eleocharis]]