View source for Polygonum

{{Treatment/ID
|accepted_name=Polygonum
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=1: 359. 1753
|year=1753
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 170. 1754
|year=1754
}}
|common_names=Knotweed
|basionyms=
|synonyms=
|hierarchy=Polygonaceae;Polygonaceae subfam. Polygonoideae;Polygonum
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Polygonaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Polygonaceae subfam. Polygonoideae]]</div><div class="higher-taxon"><small>genus</small>[[Polygonum]]</div></div>
|etymology=Greek poly, many, and gony, knee joint (traditional interpretation), or gone, seed (grammatically correct interpretation)
|volume=Volume 5
|mention_page=page 216, 217, 218, 479, 480, 481, 541, 548, 574, 589, 594
|treatment_page=page 547
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Herbs,</b> shrubs, or subshrubs, annual (perennial in <i>P. striatulum</i>), homophyllous or heterophyllous, sometimes heterocarpic; roots fibrous or woody. <b>Stems</b> prostrate to erect, glabrous, smooth or sometimes papillous-scabridulous. <b>Leaves</b> cauline, alternate (opposite in <i>P. humifusum</i>), petiolate or sessile; ocrea with distal part persistent, often hyaline, white or silvery, 2-lobed, chartaceous, glabrous, disintegrating into fibers, or disintegrating completely; petiole base articulated with ocrea or not; blade linear, lanceolate, elliptic, ovate, or subround, margins entire. <b>Inflorescences</b> axillary or axillary and terminal, spikelike, or flowers solitary; peduncle absent. <b>Pedicels</b> present or absent. <b>Flowers</b> bisexual, 1–7(–10) per ocreate fascicle, base not stipelike; perianth nonaccrescent, white or greenish white to pink, campanulate to urceolate, glabrous; tepals 5, connate 3–70% of their length, petaloid or sepaloid, monomorphic or, rarely, dimorphic, the inner usually flat, the outer flat or sometimes keeled and cucullate distally, sometimes of different length than the inner; stamens 3–8 (some may be reduced to staminodes); filaments distinct, free or adnate to perianth tube, glabrous; anthers whitish yellow, pink to purple or orange-pink, elliptic to oblong; styles (2–)3, mostly spreading, distinct or connate proximally; stigmas 2–3, capitate. <b>Achenes</b> included or exserted, yellow-green, brown, or black, unwinged, (2–)3-gonous, glabrous. <b>Seeds</b>: embryo curved. <b>x</b> = 10.</span><!--

-->{{Treatment/Body
|distribution=Nearly worldwide.
|discussion=<p>Species ca. 65 (33 in the flora).</p><!--
--><p>Two sections of <i>Polygonum</i> are recognized here. <i>Section</i> <i>Polygonum</i> is nearly cosmopolitan and best represented in north-temperate regions; sect. Duravia comprises species restricted to North America. K. Haraldson (1978) recognized both sections based on differences in stem morphology, petiole structure, and pollen morphology. J. C. Hickman (1984) described sect. Monticola and included in it species of sect. Duravia occurring mostly in montane habitats, with leaves articulated to the ocreae, one-veined, and not mucronate, proximal leaves lanceolate to round, and styles connate at their bases and neither hardened nor persistent. L.-P. Ronse Decraene and J. R. Akeroyd (1988) and L.-P. Ronse Decraene et al. (2000) included sect. Duravia in sect. <i>Polygonum</i> based on floral and fruit characters.</p><!--
--><p>Similarities in floral structure, fruit anatomy, and pollen morphology have been noted between <i>Polygonella</i> with <i>Polygonum</i> (L.-P. Ronse Decraene et al. 2000). Based on evidence from comparative morphological studies, Ronse Decraene et al. (2004) included <i>Polygonella</i> in sect. Duravia of <i>Polygonum</i>.</p><!--
--><p>Four introduced taxa of sect. <i>Polygonum</i> that were collected in the flora area at the end of the nineteenth century and beginning of the twentieth century appear not to have persisted here and are not included in the keys. <i>Polygonum</i> arenarium Waldstein & Kitaibel and P. bellardii Allioni were reported by B. L. Robinson (1902) from Rhode Island and Massachusetts, respectively. The former resembles <i>P. patulum</i> but has open flowers. <i>Polygonum</i> bellardii is discussed below under <i>P. ramosissimum</i>. <i>Polygonum</i> polycnemoides Jaubert & Spach and <i>P. humifusum</i> C. Merck ex K. Koch subsp. humifusum were reported by J. F. Brenckle (1941). The former was collected in New York City in 1894 and in Idaho in 1940. It differs from all other <i>Polygonum</i> species in having a tube 55–70% of the perianth length. <i>Polygonum humifusum</i> subsp. humifusum is discussed below under <i>P. humifusum </i>subsp.<i> caurianum</i>.</p>
|tables=
|references={{Treatment/Reference
|id=jones1970a
|text=Jones, D. M. and T. R. Mertens. 1970. A taxonomic study of genus Polygonum employing chromatographic methods. Proc. Indiana Acad. Sci. 80: 422–430.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  <h3 class="treatment-key-header" id="key-0">Key to the Sections of Polygonum</h3>
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Stems distinctly and ± regularly 8-16-ribbed; leaf blade venation pinnate, secondary veins conspicuous; anthers whitish yellow; nearly worldwide
|[[Polygonum sect. Polygonum|Polygonum sect. Polygonum]]
|-id=key-0-1
|1
|Stems 4-gonous, ribs obscure or absent; leaf blade venation parallel, secondary veins not conspicuous; anthers pink to purple; mostly w North America
|[[Polygonum sect. Duravia|Polygonum sect. Duravia]]
|}
</div></div><!--

-->{{#Taxon:
name=Polygonum
|author=Mihai Costea;François J. Tardif;Harold R. Hinds†
|authority=Linnaeus
|rank=genus
|parent rank=subfamily
|synonyms=
|basionyms=
|family=Polygonaceae
|illustrator=Yevonn Wilson-Ramsey
|illustration copyright=Flora of North America Association
|distribution=Nearly worldwide.
|reference=jones1970a
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=1753;1754
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V5/V5_1117.xml
|subfamily=Polygonaceae subfam. Polygonoideae
|genus=Polygonum
}}<!--

-->[[Category:Treatment]][[Category:Polygonaceae subfam. Polygonoideae]]