View source for Potamogeton pusillus

{{Treatment/ID
|accepted_name=Potamogeton pusillus
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=1: 127. 1753 (as pusillum)
}}
|special_status={{Treatment/ID/Special_status
|code=W
|label=Weedy
}}
|basionyms=
|synonyms=
|hierarchy=Potamogetonaceae;Potamogeton;Potamogeton pusillus
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Potamogetonaceae]]</div><div class="higher-taxon"><small>genus</small>[[Potamogeton]]</div><div class="higher-taxon"><small>species</small>[[Potamogeton pusillus]]</div></div>
|volume=Volume 22
|mention_page=
|treatment_page=
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Rhizomes </b>absent. <b>Cauline</b> stems terete to slightly compressed, without spots, 18–150 cm; glands present on at least some nodes, green, gold, brown, or rarely white, to 0.5 mm diam. <b>Turions</b> common, soft, lateral or terminal, 0.9–3.2 cm × 0.3–1.8 mm, soft; leaves &#177; 2-ranked; outer leaves 1–3 per side, base not corrugate, apex subulate to obtuse; inner leaves rolled into hardened fusiform structure. <b>Leaves</b> submersed, &#177; spirally arranged, sessile, delicate to coarse; stipules persistent, inconspicuous, connate or convolute, free from base of blade, brown to green or white, not ligulate, 0.31–0.92 cm, rarely appearing fibrous, not shredding at tip, apex obtuse; blade pale green to olive-green, rarely somewhat reddish, linear, not arcuate, 0.9–6.5 cm × 0.2–2.5 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, subulate to obtuse, lacunae absent or present, in 0–5 rows each side of midrib; veins 1–3(–5). <b>Inflorescences</b> unbranched, submersed or emersed; peduncles not dimorphic, axillary or terminal, erect, rarely recurved, filiform to slightly clavate, 0.5–6.2(–6.6) cm; spikes not dimorphic, capitate to cylindric, 1.5–10.1 mm. <b>Fruits</b> sessile, green to brown, ovoid to obovoid, turgid to concave, not abaxially or laterally keeled, 1.5–2.2 × 1.2–1.6 mm; beak erect, 0.1–0.6; sides without basal tubercles; embryo with less than 1 full spiral.</span><!--

-->{{Treatment/Body
|distribution=Alta.;B.C.;Man.;N.B.;N.S.;N.W.T.;Nunavut;Ont.;P.E.I.;Que.;Sask.;Yukon;Ala.;Alaska;Ariz.;Ark.;Calif.;Colo.;Conn.;D.C.;Del.;Fla.;Ga.;Idaho;Ill.;Ind.;Iowa;Kans.;Ky.;La.;Maine;Mass.;Md.;Mich.;Minn.;Miss.;Mo.;Mont.;N.C.;N.Dak.;N.H.;N.J.;N.Mex.;N.Y.;Nebr.;Nev.;Ohio;Okla.;Oreg.;Pa.;R.I.;S.C.;S.Dak.;Tenn.;Tex.;Utah;Va.;Vt.;W.Va.;Wash.;Wis.;Wyo.;nearly worldwide.
|discussion=<p>Three hybrids, <i>Potamogeton perfoliatus</i> × <i>P. pusillus</i> (= P. × mysticus Morong), <i>P. friesii</i> × <i>P. pusillus</i> (= P. × pusilliformis Fisher [P. × intermedius Fischer]), and <i>P. obtusifolius</i> × <i>P. pusillus</i> (= P. × saxonicus Hagstr&ouml;m), have been described.</p><!--
--><p>Subspecies 3 (3 in the flora).</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Leaf blade 1-veined, subulate, 0.2–0.7 mm wide; New England and s Quebec.
|[[Potamogeton pusillus subsp. gemmiparus|Potamogeton pusillus subsp. gemmiparus]]
|-id=key-0-1
|1
|Leaf blade 1–5-veined, acute to obtuse, 0.2–2.5 mm wide; widespread throughout North America.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Mature fruits obovoid, sides concave; beak toward adaxial edge, rarely median; peduncles filiform to cylindric, 1–3 per plant; inflorescences interrupted; leaf blade with 0–2 rows of lacunae along midrib, apex acute, rarely apiculate, rarely with bristle; stipules connate.
|[[Potamogeton pusillus subsp. pusillus|Potamogeton pusillus subsp. pusillus]]
|-id=key-0-2
|2
|Mature fruits widest at middle or ovoid, sides rounded; beak median, not toward adaxial edge; peduncles cylindric, more than 3 per plant; inflorescences continuous; leaf blade with 1–5 rows of lacunae along midrib, apex acute to obtuse; stipules convolute.
|[[Potamogeton pusillus subsp. tenuissimus|Potamogeton pusillus subsp. tenuissimus]]
|}
</div></div><!--

-->{{#Taxon:
name=Potamogeton pusillus
|authority=Linnaeus
|rank=species
|parent rank=genus
|synonyms=
|basionyms=
|family=Potamogetonaceae
|distribution=Alta.;B.C.;Man.;N.B.;N.S.;N.W.T.;Nunavut;Ont.;P.E.I.;Que.;Sask.;Yukon;Ala.;Alaska;Ariz.;Ark.;Calif.;Colo.;Conn.;D.C.;Del.;Fla.;Ga.;Idaho;Ill.;Ind.;Iowa;Kans.;Ky.;La.;Maine;Mass.;Md.;Mich.;Minn.;Miss.;Mo.;Mont.;N.C.;N.Dak.;N.H.;N.J.;N.Mex.;N.Y.;Nebr.;Nev.;Ohio;Okla.;Oreg.;Pa.;R.I.;S.C.;S.Dak.;Tenn.;Tex.;Utah;Va.;Vt.;W.Va.;Wash.;Wis.;Wyo.;nearly worldwide.
|reference=None
|publication title=Sp. Pl.
|publication year=
|special status=Weedy
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V22/V22_290.xml
|genus=Potamogeton
|species=Potamogeton pusillus
}}<!--

-->[[Category:Treatment]][[Category:Potamogeton]]