View source for Eleocharis macrostachya

{{Treatment/ID
|accepted_name=Eleocharis macrostachya
|accepted_authority=Britton in J. K. Small
|publications={{Treatment/Publication
|title=in J. K. Small, Fl. S.E. U.S.,
|place=184, 1327. 1903
|year=1903
}}
|common_names=Éléocharide à gros épi
|special_status={{Treatment/ID/Special_status
|code=F
|label=Illustrated
}}
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Eleocharis perlonga
|authority=Fernald & Brackett
|rank=species
}} {{Treatment/ID/Synonym
|name=Eleocharis xyridiformis
|authority=Fernald & Brackett
|rank=species
}}
|hierarchy=Cyperaceae;Eleocharis;Eleocharis subg. Eleocharis;Eleocharis sect. Eleocharis;Eleocharis (sect. Eleocharis) ser. Eleocharis;Eleocharis macrostachya
|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. Eleocharis]]</div><div class="higher-taxon"><small>section</small>[[Eleocharis sect. Eleocharis]]</div><div class="higher-taxon"><small>series</small>[[Eleocharis (sect. Eleocharis) ser. Eleocharis]]</div><div class="higher-taxon"><small>species</small>[[Eleocharis macrostachya]]</div></div>
|volume=Volume 23
|mention_page=page 64, 72, 73, 75, 76, 78
|treatment_page=page 74
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole_organism duration;whole_organism growth form;whole_organism growth form"><b>Plants </b>perennial, mat-forming;</span> <span class="statement" id="st-d0_s1" data-properties="rhizome prominence;rhizome length or size;rhizome thickness;rhizome texture;cortex duration;longer internode some measurement;scale duration;scale some measurement;scale texture;scale texture">rhizomes evident, long, 1–2 mm thick, firm, cortex persistent, longer internodes 10–55 mm, scales often fugaceous, 5–10 mm, membranous, not fibrous.</span> <span class="statement" id="st-d0_s2" data-properties="culm shape;culm width or width;ridge quantity;ridge shape;ridge length;ridge atypical width;ridge width;ridge texture;ridge texture"><b>Culms </b>terete to markedly compressed, to 3 times wider than thick, often with to 25 blunt ridges when dry, 10–100 cm × 0.5–2.5 (–3.5) mm, firm (to soft), internally spongy.</span> <span class="statement" id="st-d0_s3" data-properties="distal sheath duration;distal sheath architecture or dehiscence;distal sheath coloration;distal sheath coloration;distal sheath texture;apex shape;tooth presence;tooth atypical some measurement;tooth some measurement"><b>Leaves:</b> distal leaf-sheaths persistent, rarely splitting abaxially, proximally mostly red, distally green (or red), papery (to membranous), apex truncate to obtuse, tooth sometimes present on some or all culms, 0.1–0.6 (–1) mm.</span> <span class="statement" id="st-d0_s4" data-properties="spikelet shape;spikelet length;spikelet width;spikelet shape;spikelet shape"><b>Spikelets </b>narrowly lanceoloid to ovoid, 5–40 × 2–5 mm, acute, rarely obtuse;</span> <span class="statement" id="st-d0_s5" data-properties="proximal scale architecture or fixation;proximal scale quantity;culm architecture">proximal scale clasping (2/3–) 3/4 or more of culm to amplexicaulous, usually variably in same plant;</span> <span class="statement" id="st-d0_s6" data-properties="subproximal scale architecture;subproximal scale architecture;subproximal scale architecture">subproximal scale empty or with flower, usually empty in some spikelets and with flower in other spikelets in same plant;</span> <span class="statement" id="st-d0_s7" data-properties="floral scale duration;floral scale orientation;floral scale size;floral scale coloration;floral scale coloration;floral scale coloration;fruit quantity;fruit quantity;midrib region coloration;midrib region shape;midrib region length;midrib region width;midrib region architecture or shape;midrib region shape">floral scales deciduous, often spreading in fruit, 30–80, 3–5 per mm of rachilla, medium brown, sometimes redbrown or dark chestnut-brown, midrib regions often stramineous to green, ovate to narrowly lanceolate, 2.5–5.5 × 1.5–2.5 mm, entire, mostly carinate in distal part of spikelet.</span> <span class="statement" id="st-d0_s8" data-properties="perianth bristle atypical quantity;perianth bristle quantity;perianth bristle prominence;perianth bristle presence;perianth bristle coloration;perianth bristle size;perianth bristle height or length or size;tubercle variability"><b>Flowers:</b> perianth bristles 4 (–5), sometimes rudimentary or absent, brown, slender to stout, much shorter than achene to equaling tubercle;</span> <span class="statement" id="st-d0_s9" data-properties="stamen quantity">stamens 3;</span> <span class="statement" id="st-d0_s10" data-properties="anther coloration;anther some measurement">anthers dark yellow to orangebrown, 1.3–2.7 mm;</span> <span class="statement" id="st-d0_s11" data-properties="style shape">styles 2-fid.</span> <span class="statement" id="st-d0_s12" data-properties="achene duration;achene coloration;achene life cycle;achene coloration;achene coloration;achene shape;achene shape;achene shape;achene shape;angle prominence;angle length;angle width;apex shape;neck presence;neck height or length or size;neck architecture or pubescence or relief;neck relief;ridge quantity;series orientation"><b>Achenes </b>not persistent, yellow maturing to yellowbrown or dark-brown, ellipsoid, obovoid, or obpyriform, biconvex to planoconvex, angles obscure, 1.1–1.9 × 0.8–1.5 mm, apex rounded, neck absent or short, smooth at 30X, or finely rugulose at 10–20X with 20 or more horizontal ridges in a vertical series.</span> <span class="statement" id="st-d0_s13" data-properties="tubercle coloration;tubercle shape;tubercle length;tubercle width;wide position;wide position;2n chromosome quantity;2n chromosome quantity;2n chromosome quantity"><b>Tubercles </b>brown to whitish, pyramidal, as high as or sometimes much higher than wide, 0.35–0.7 × 0.25–0.7 mm. <b>2n</b> = 18, 19, 38.</span><!--

-->{{Treatment/Body
|phenology=Fruiting spring–summer, all year in s Texas and Louisiana.
|habitat=Fresh to slightly brackish or alkaline shores, stream beds, swales, vernal pools, pastures, ditches, artificial ponds
|elevation=10–2300 m
|distribution=Alta.;B.C.;Man.;Ont.;Que.;Yukon;Alaska;Ariz.;Ark.;Calif.;Colo.;Idaho;Ill.;Iowa;Kans.;La.;Minn.;Miss.;Mo.;Mont.;Nebr.;Nev.;N.Mex.;N.Dak.;Okla.;Oreg.;S.Dak.;Tex.;Utah;Wash.;Wis.;Wyo.;Mexico;South America (Argentina);South America (Colombia);South America (Uruguay)
|discussion=<p>The chromosome numbers 2n = 10 and 2n = 16 have also been reported from North America but have not been verified.</p><!--
--><p>Eleocharis macrostachya probably occurs in Saskatchewan; I have not seen specimens. It is extremely variable. Cytotaxonomic studies (S.-O. Strandhede 1967; L. J. Harms 1968) and morphology suggest that it is a diploid-polyploid complex at least partly of hybrid origin from E. palustris and both E. erythropoda and E. uniglumis. The 2n = 38 plants of E. macrostachya may comprise the American counterpart of the European E. palustris subsp. vulgaris, which presumably originated from E. palustris subsp. palustris and E. uniglumis (S.-O. Strandhede 1966). Although recognition of infraspecific taxa is premature, the following three intergrading variants are notable:</p><!--
--><p>Variant a (= Eleocharis xyridiformis) almost certainly deserves taxonomic recognition, perhaps as a species. It has markedly compressed culms to 3 times wider than thick; distal leaf-sheath apices subtruncate, usually with a tooth to 0.6(–1) mm on some or all culms; spikelets narrowly lanceoloid; floral scales medium brown to stramineous, mostly lanceolate and carinate, 2.5–4 × 1.5 mm; achenes 1.1–1.5 × 0.8–1.2 mm; chromosome numbers (for which I have seen vouchers, all from Kansas and South Dakota), 2n = 18. It is known from 20–450 m in Arizona, California, Illinois, Kansas, Missouri, New Mexico, Oklahoma, South Dakota, Texas, and Mexico (Coahuila, Durango, Nuevo León). Both the holotype of E. xyridiformis from Mexico and the vouchers of the 2n = 18 chromosome counts reported for E. xyridiformis, all from Kansas and South Dakota, have stomates 55–60 µm, which is typical of 2n = 18 plants (S.-O. Strandhede 1967). The holotype of E. macrostachya from Oklahoma, which is otherwise much like the type of E. xyridiformis except for less markedly compressed culms, has stomates averaging 59–68 µm, which is typical of plants of E. macrostachya with 2n = 38 as in variant b.</p><!--
--><p>Variant b is very variable in comparison with variant a. It differs from variant a in having culms terete or slightly compressed; distal leaf-sheath apices often obtuse, tooth rarely present, to 0.1 mm; spikelets broadly lanceoloid to ovoid; floral scales 3.5–4(–4.5) × 1.7–2+ mm; achenes 1.3–1.5 mm, rarely to 1.8 mm; culm stomates 60–72 µm; chromosome numbers (for which I have seen vouchers, all from Kansas and South Dakota), 2n = ca. 38. It is wide-ranging, known from inland localities at 20–2300 m from Manitoba west to Yukon and British Columbia, south to Alabama, Mississippi, Louisiana, Texas, New Mexico, Arizona, and California, and in Mexico from Baja California. Intermediates between variant b and both Eleocharis erythropoda and E. uniglumis are widespread, and intermediates with E. ambigens occur in Louisiana. Most plants of variant b have floral scales to 4 mm and achenes to 1.5 mm; plants with scales to 4–5 mm and achenes sometimes more than 1.6 mm occur in California, Nevada, Oregon, and Washington.</p><!--
--><p>Variant c differs from variant b in having spikelet scales mostly uniformly dark chestnut-brown, not carinate, (3.5–)4–5.5 × 2–2.5 mm. Its achenes are often unusually large, 1.3–1.8(–2) × 1.1–1.5 mm. It is known from near sea level on the coasts of British Columbia, Ontario, and Quebec (James Bay and Magdalen Islands); Alaska, California, Oregon, and Washington. Some plants are intermediate between variant c and variant b. Several specimens I have seen from far eastern Russia are very similar to American plants of Eleocharis macrostachya, variant c. Except for having incompletely amplexicaulous proximal scales, and subproximal scales often without a flower, variant c closely resembles many Eurasian specimens of E. uniglumis.</p>
|tables=
|references=
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-->{{#Taxon:
name=Eleocharis macrostachya
|authority=Britton in J. K. Small
|rank=species
|parent rank=series
|synonyms=Eleocharis perlonga;Eleocharis xyridiformis
|basionyms=
|family=Cyperaceae
|phenology=Fruiting spring–summer, all year in s Texas and Louisiana.
|habitat=Fresh to slightly brackish or alkaline shores, stream beds, swales, vernal pools, pastures, ditches, artificial ponds
|elevation=10–2300 m
|distribution=Alta.;B.C.;Man.;Ont.;Que.;Yukon;Alaska;Ariz.;Ark.;Calif.;Colo.;Idaho;Ill.;Iowa;Kans.;La.;Minn.;Miss.;Mo.;Mont.;Nebr.;Nev.;N.Mex.;N.Dak.;Okla.;Oreg.;S.Dak.;Tex.;Utah;Wash.;Wis.;Wyo.;Mexico;South America (Argentina);South America (Colombia);South America (Uruguay)
|reference=None
|publication title=in J. K. Small, Fl. S.E. U.S.,
|publication year=1903
|special status=Illustrated
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V23/V23_99.xml
|genus=Eleocharis
|subgenus=Eleocharis subg. Eleocharis
|section=Eleocharis sect. Eleocharis
|series=Eleocharis (sect. Eleocharis) ser. Eleocharis
|species=Eleocharis macrostachya
|2n chromosome quantity=38;19;18
|achene coloration=dark-brown;yellowbrown;yellow
|achene duration=not persistent
|achene life cycle=maturing
|achene shape=obpyriform biconvex;planoconvex
|angle length=1.1mm;1.9mm
|angle prominence=obscure
|angle width=0.8mm;1.5mm
|anther coloration=dark yellow;orangebrown
|anther some measurement=1.3mm;2.7mm
|apex shape=rounded;truncate;obtuse
|cortex duration=persistent
|culm architecture=amplexicaulous
|culm shape=terete;markedly compressed
|culm width or width=0-3 times wider than thick
|distal sheath architecture or dehiscence=splitting
|distal sheath coloration=green;red
|distal sheath duration=persistent
|distal sheath texture=papery
|floral scale coloration=dark chestnut-brown;redbrown;brown
|floral scale duration=deciduous
|floral scale orientation=spreading
|floral scale size=medium
|fruit quantity=3;5
|longer internode some measurement=10mm;55mm
|midrib region architecture or shape=entire
|midrib region coloration=stramineous;green
|midrib region length=2.5mm;5.5mm
|midrib region shape=carinate;ovate;narrowly lanceolate
|midrib region width=1.5mm;2.5mm
|neck architecture or pubescence or relief=smooth
|neck height or length or size=short
|neck presence=absent
|neck relief=rugulose
|perianth bristle atypical quantity=4;5
|perianth bristle coloration=brown
|perianth bristle height or length or size=much shorter
|perianth bristle presence=absent
|perianth bristle prominence=rudimentary
|perianth bristle quantity=4
|perianth bristle size=slender;stout
|proximal scale architecture or fixation=clasping
|proximal scale quantity=2/3;3/4
|rhizome length or size=long
|rhizome prominence=evident
|rhizome texture=firm
|rhizome thickness=1mm;2mm
|ridge atypical width=2.5mm;3.5mm
|ridge length=10cm;100cm
|ridge quantity=20;0;25
|ridge shape=blunt
|ridge texture=spongy;firm
|ridge width=0.5mm;2.5mm
|scale duration=fugaceous
|scale some measurement=5mm;10mm
|scale texture=not fibrous;membranous
|series orientation=vertical
|spikelet length=5mm;40mm
|spikelet shape=obtuse;acute;narrowly lanceoloid;ovoid
|spikelet width=2mm;5mm
|stamen quantity=3
|style shape=2-fid
|subproximal scale architecture=empty;with flower;empty
|tooth atypical some measurement=0.6mm;1mm
|tooth presence=absent
|tooth some measurement=0.1mm;0.6mm
|tubercle coloration=brown;whitish
|tubercle length=0.35mm;0.7mm
|tubercle shape=pyramidal
|tubercle variability=equaling
|tubercle width=0.25mm;0.7mm
|whole_organism duration=perennial
|whole_organism growth form=plant;mat-forming
|wide position=higher;higher
}}<!--

-->[[Category:Treatment]][[Category:Eleocharis (sect. Eleocharis) ser. Eleocharis]]