View source for Lemna

{{Treatment/ID
|accepted_name=Lemna
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=2: 970. 1753; Gen. Pl. ed. 5; 417, 1754
|year=1754
}}
|common_names=Duckweed;lenticules
|basionyms=
|synonyms=
|hierarchy=Lemnaceae;Lemna
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Lemnaceae]]</div><div class="higher-taxon"><small>genus</small>[[Lemna]]</div></div>
|etymology=Greek name of a water plant
|volume=Volume 22
|mention_page=
|treatment_page=page 146
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Roots </b>1 per frond. <b>Fronds</b> floating or submersed, 1 or 2–20 or more, coherent in groups or forming chains, lanceolate-ovate, flat or gibbous, 1–15 mm, margins entire or denticulate, upper surfaces sometimes with small conic papillae along veins (especially at node and near apex); air spaces in tissue; reproductive pouches 2, lateral, at base from which daughter fronds and flowers originate, triangular; veins 1–5(–7), originating from point in proximal part of frond (node) or if more than 3 veins present, outer ones sometimes branching distally from inner ones; scale at base of frond absent; anthocyanins sometimes present; pigment cells absent (red pigmentation present in some species); turions absent (sometimes present in <i>L. turionifera</i>). <b>Flowers</b> 1(–2) per frond, surrounded by small utricular, membranous scale; stamens 2, 4-locular. <b>Seeds</b> 1–5, longitudinally ribbed. <b>x</b> = 10, 21, 22</span><!--

-->{{Treatment/Body
|distribution=Worldwide except arctic and antarctic regions.
|discussion=<p>In <i>Lemna</i> the connection to the mother frond is formed by a thin white stipe at the base that falls off or decays after the frond is grown (frond of <i>L. trisulca</i> is narrowed at base into a green stalk persisting on frond).</p><!--
--><p>Species 13 (9 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
|Fronds submersed (except when flowering or fruiting), margins denticulate distally, 2–3.5 times as long as wide, base suddenly narrowed into green stalk, 2–20 mm.
|[[Lemna trisulca|Lemna trisulca]]
|-id=key-0-1
|1
|Fronds floating, margins entire, 1–3 times as long as wide.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Fronds with 1 vein.
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Fronds with 3–5(–7) veins.
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Vein mostly prominent, longer than extension of air spaces, or running through at least 3/4 distance between node and apex
|[[Lemna valdiviana|Lemna valdiviana]]
|-id=key-0-3
|3
|Vein sometimes indistinct, very rarely longer than extension of air spaces, not longer than 2/3 distance between node and apex
|[[Lemna minuta|Lemna minuta]]
|-id=key-0-4
|4
|Root sheath winged at base; root tip usually sharp pointed; roots to 3(–3.5) cm; fronds without reddish color or spots of anthocyanin, mostly with 1 very distinct papilla near apex on upper surface.
|[[#key-0-5| > 5]]
|-id=key-0-4
|4
|Root sheath not winged; root tip mostly rounded; roots often longer than 3 cm; fronds often with reddish tinge or spots of anthocyanin, with or without distinct papilla near apex on upper surface.
|[[#key-0-6| > 6]]
|-id=key-0-5
|5
|Seeds with 35–70 indistinct ribs (to count ribs remove membranous pericarp), staying within fruit wall after ripening; root sheath wing 2–3 times as long as wide
|[[Lemna perpusilla|Lemna perpusilla]]
|-id=key-0-5
|5
|Seeds with 8–26 distinct ribs, falling out of fruit wall after ripening; root sheath wing 1–2.5 times as long as wide
|[[Lemna aequinoctialis|Lemna aequinoctialis]]
|-id=key-0-6
|6
|Plants forming small, olive to brown, rootless turions, which sink to bottom
|[[Lemna turionifera|Lemna turionifera]]
|-id=key-0-6
|6
|Plants usually without distinct turions.
|[[#key-0-7| > 7]]
|-id=key-0-7
|7
|Largest air spaces longer than 0.3 mm; if red-colored on lower surface, coloring beginning from margin; ovary (1–)2–7-ovulate
|[[Lemna gibba|Lemna gibba]]
|-id=key-0-7
|7
|Largest air spaces 0.3 mm or shorter; if pigmented on lower surface, red coloring beginning from attachment point of root; ovary 1-ovulate.
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Fronds not reddish on lower surface (or at least much less so than on upper); greatest distance between lateral veins near or proximal to middle.
|[[Lemna minor|Lemna minor]]
|-id=key-0-8
|8
|Fronds often reddish on lower surface (more intensely so than on upper); greatest distance between lateral veins near or distal to middle.
|[[#key-0-9| > 9]]
|-id=key-0-9
|9
|Fronds flat, with mostly distinct papillae on midline of upper surface; seeds with 30–60 indistinct ribs
|[[Lemna turionifera|Lemna turionifera]]
|-id=key-0-9
|9
|Fronds often gibbous, with very distinct papillae above node and near apex on upper surface but not between node and apex; seeds with 10–16 distinct ribs
|[[Lemna obscura|Lemna obscura]]
|}
</div></div><!--

-->{{#Taxon:
name=Lemna
|author=
|authority=Linnaeus
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Lemnaceae
|distribution=Worldwide except arctic and antarctic regions.
|reference=None
|publication title=Sp. Pl.
|publication year=1754
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V22/V22_243.xml
|genus=Lemna
}}<!--

-->[[Category:Treatment]][[Category:Lemnaceae]]