Difference between revisions of "Lemna"
Sp. Pl. 2: 970. 1753; Gen. Pl. ed. 5; 417, 1754.
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− | --><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 L. turionifera). <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><!-- | + | --><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 | -->{{Treatment/Body | ||
|distribution=Worldwide except arctic and antarctic regions. | |distribution=Worldwide except arctic and antarctic regions. | ||
− | |discussion=<p>In Lemna 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 L. trisulca is narrowed at base into a green stalk persisting on frond).</p><!-- | + | |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> | --><p>Species 13 (9 in the flora).</p> | ||
|tables= | |tables= | ||
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|publication year=1754 | |publication year=1754 | ||
|special status= | |special status= | ||
− | |source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/ | + | |source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/8f726806613d60c220dc4493de13607dd3150896/coarse_grained_fna_xml/V22/V22_243.xml |
|genus=Lemna | |genus=Lemna | ||
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-->[[Category:Treatment]][[Category:Lemnaceae]] | -->[[Category:Treatment]][[Category:Lemnaceae]] |
Revision as of 15:56, 18 September 2019
Roots 1 per frond. Fronds 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 L. turionifera). Flowers 1(–2) per frond, surrounded by small utricular, membranous scale; stamens 2, 4-locular. Seeds 1–5, longitudinally ribbed. x = 10, 21, 22
Distribution
Worldwide except arctic and antarctic regions.
Discussion
In Lemna 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 L. trisulca is narrowed at base into a green stalk persisting on frond).
Species 13 (9 in the flora).
Selected References
None.
Lower Taxa
Key
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 |
1 | Fronds floating, margins entire, 1–3 times as long as wide. | > 2 |
2 | Fronds with 1 vein. | > 3 |
2 | Fronds with 3–5(–7) veins. | > 4 |
3 | Vein mostly prominent, longer than extension of air spaces, or running through at least 3/4 distance between node and apex | Lemna valdiviana |
3 | Vein sometimes indistinct, very rarely longer than extension of air spaces, not longer than 2/3 distance between node and apex | Lemna minuta |
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. | > 5 |
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. | > 6 |
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 |
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 |
6 | Plants forming small, olive to brown, rootless turions, which sink to bottom | Lemna turionifera |
6 | Plants usually without distinct turions. | > 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 |
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. | > 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 |
8 | Fronds often reddish on lower surface (more intensely so than on upper); greatest distance between lateral veins near or distal to middle. | > 9 |
9 | Fronds flat, with mostly distinct papillae on midline of upper surface; seeds with 30–60 indistinct ribs | Lemna turionifera |
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 |