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<title>Merosity</title>
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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Merosity</span></span>
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<p><b>Merosity</b> (from the greek "méros," which means "having parts") refers to the number of component parts in a distinct <a href="Whorl_(botany)" title="Whorl (botany)">whorl</a> of a plant structure.<sup id="cite_ref-Ronse_Decraene_and_Smets_1994_1-0" class="reference"><a href="#cite_note-Ronse_Decraene_and_Smets_1994-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The term is most commonly used in the context of a <a href="Flower" title="Flower">flower</a> where it refers to the number of <a href="Sepal" title="Sepal">sepals</a> in a whorl of the calyx, the number of <a href="Petal" title="Petal">petals</a> in a whorl of the corolla, the number of <a href="Stamen" title="Stamen">stamens</a> in a whorl of the <a href="Androecium" class="mw-redirect" title="Androecium">androecium</a>, or the number of carpels in a whorl of the <a href="Gynoecium" title="Gynoecium">gynoecium</a>. The term may also be used to refer to the number of leaves in a <a href="Leaf" title="Leaf">leaf</a> whorl.
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<table class="wikitable">
<tbody><tr>
<th scope="col" style="width: 8em;">
</th>
<th scope="col" style="width: 16em;">Noun
</th>
<th scope="col" style="width: 16em;">Adjective
</th></tr>
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<td>2 parts</td>
<td>dimery</td>
<td>dimerous, 2-merous
</td></tr>
<tr style="text-align: center;">
<td>3 parts</td>
<td>trimery</td>
<td>trimerous, 3-merous
</td></tr>
<tr style="text-align: center;">
<td>4 parts</td>
<td>tetramery</td>
<td>tetramerous, 4-merous
</td></tr>
<tr style="text-align: center;">
<td>5 parts</td>
<td>pentamery</td>
<td>pentamerous, 5-merous
</td></tr>
<tr style="text-align: center;">
<td>many parts</td>
<td>polymery</td>
<td>polymerous
</td></tr>
<tr style="text-align: center;">
<td>few parts</td>
<td>oligomery</td>
<td>oligomerous
</td></tr></tbody></table>
<p>The adjective <i>n</i>-merous refers to a whorl of <i>n</i> parts, where <i>n</i> is any integer greater than one.
</p><p>In nature, five or three parts per whorl have the highest frequency of occurrence, but four or two parts per whorl are not uncommon. Two consecutive whorls of dimerous petals are often mistaken for tetramerous petals.<sup id="cite_ref-Ronse_Decraene_and_Smets_1994_1-1" class="reference"><a href="#cite_note-Ronse_Decraene_and_Smets_1994-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>If all of the whorls in a given floral arrangement have the same merosity, the flower is said to be <b>isomerous</b>, otherwise the flower is <b>anisomerous</b>.<sup id="cite_ref-latindict_2-0" class="reference"><a href="#cite_note-latindict-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> For example, <i><a href="Trillium" title="Trillium">Trillium</a></i> is isomerous since all whorls are trimerous (one whorl of three sepals, zero or one whorl of three petals, two whorls of three stamens each, and one whorl of three carpels). <i>Trillium</i> also has one whorl of three leaves.
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<tbody><tr>
<th scope="col" style="width: 8em;">
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<th scope="col" style="width: 16em;">Noun
</th>
<th scope="col" style="width: 16em;">Adjective
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<td>equal parts</td>
<td>isomery</td>
<td>isomerous
</td></tr>
<tr style="text-align: center;">
<td>unequal parts</td>
<td>anisomery</td>
<td>anisomerous
</td></tr></tbody></table>
<div class="mw-heading mw-heading2"><h2 id="Gallery">Gallery</h2></div>
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</style><div class="thumb tmulti tleft"><div class="thumbinner multiimageinner" style="width:792px;max-width:792px"><div class="trow"><div class="tsingle" style="width:205px;max-width:205px"><div class="thumbimage" style="height:202px;overflow:hidden"><span typeof="mw:File"></span></div><div class="thumbcaption text-align-center">Trimerous flower of <i><a href="Tulipa_clusiana" title="Tulipa clusiana">Tulipa clusiana</a></i> (the three sepals resemble petals)</div></div><div class="tsingle" style="width:275px;max-width:275px"><div class="thumbimage" style="height:202px;overflow:hidden"><span typeof="mw:File"></span></div><div class="thumbcaption text-align-center">Tetramerous flower of <i><a href="Correa_alba" title="Correa alba">Correa alba</a></i></div></div><div class="tsingle" style="width:306px;max-width:306px"><div class="thumbimage" style="height:202px;overflow:hidden"><span typeof="mw:File"></span></div><div class="thumbcaption text-align-center">Pentamerous flower of <i><a href="Crassula_ovata" title="Crassula ovata">Crassula ovata</a></i></div></div></div></div></div>
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<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Cyclic_flower" title="Cyclic flower">Cyclic flower</a></li>
<li><a href="Floral_diagram" title="Floral diagram">Floral diagram</a></li>
<li><a href="Floral_formula" title="Floral formula">Floral formula</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<li id="cite_note-Ronse_Decraene_and_Smets_1994-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Ronse_Decraene_and_Smets_1994_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Ronse_Decraene_and_Smets_1994_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
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</style><cite id="CITEREFRonse_DecraeneSmets1994" class="citation journal cs1">Ronse Decraene, L. P.; Smets, E. F. (1994). <a rel="nofollow" class="external text" href="https://www.academia.edu/25486804">"Merosity in flowers: definition, origin, and taxonomic significance"</a>. <i>Plant Systematics and Evolution</i>. <b>191</b> (<span class="nowrap">1–</span>2): <span class="nowrap">83–</span>104. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1994PSyEv.191...83R">1994PSyEv.191...83R</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00985344">10.1007/BF00985344</a><span class="reference-accessdate">. Retrieved <span class="nowrap">22 November</span> 2019</span>.</cite></span>
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<li id="cite_note-latindict-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-latindict_2-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFEckel" class="citation web cs1">Eckel, P. M. <a rel="nofollow" class="external text" href="http://www.mobot.org/mobot/latindict/keyDetail.aspx?keyWord=merus">"A Grammatical Dictionary of Botanical Latin"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">22 November</span> 2019</span>.</cite></span>
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