View source for Polygonum douglasii

{{Treatment/ID
|accepted_name=Polygonum douglasii
|accepted_authority=Greene
|publications={{Treatment/Publication
|title=Bull. Calif. Acad. Sci.
|place=1: 125. 1885
|year=1885
}}
|common_names=Douglas’s knotweed;renouée de Douglas
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Polygonum douglasii var. latifolium
|authority=(Engelmann) Greene
|rank=variety
}} {{Treatment/ID/Synonym
|name=Polygonum emaciatum
|authority=(Small) Greene
|rank=species
}} {{Treatment/ID/Synonym
|name=Polygonum montanum
|authority=Michaux
|rank=species
}} {{Treatment/ID/Synonym
|name=Polygonum tenue var. commune
|authority=Engelmann
|rank=variety
}} {{Treatment/ID/Synonym
|name=Polygonum tenue var. latifolium
|authority=Engelmann
|rank=variety
}}
|hierarchy=Polygonaceae;Polygonaceae subfam. Polygonoideae;Polygonum;Polygonum sect. Duravia;Polygonum douglasii
|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 class="higher-taxon"><small>section</small>[[Polygonum sect. Duravia]]</div><div class="higher-taxon"><small>species</small>[[Polygonum douglasii]]</div></div>
|volume=Volume 5
|mention_page=page 562, 568
|treatment_page=page 567
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Herbs.</b> Stems erect, green, simple or branched, not wiry, 5–80 cm, glabrous or sparsely papillose-scabridulous. <b>Leaves</b> uniformly distributed, articulated to ocreae, basal leaves caducous, distal leaves abruptly reduced to bracts; ocrea 6–12 mm, glabrous or minutely papillose-scabridulous, proximal part cylindric, distal part hyaline, lacerate; petiole 0.1–2 mm; blade 1-veined, not pleated, linear, narrow-oblong, or oblanceolate, 15–55 × 2–8(–12) mm, margins revolute, smooth or papillose-denticulate; apex acute to mucronate. <b>Inflorescences</b> axillary and terminal, spikelike, elongate; cymes widely spaced along branches, 2–4-flowered. <b>Pedicels</b> mostly exserted from ocreae, reflexed, 2–6 mm. <b>Flowers</b> closed; perianth 3–4.5 mm; tube 20–28% of perianth length; tepals overlapping, green to tannish with white or pink margins, petaloid, oblong, cucullate, navicular, apex rounded; midveins usually branched, rarely unbranched; stamens 8. <b>Achenes</b> enclosed in perianth, black, elliptic or oblong to ovate, 3–4(–4.5) mm, faces subequal, shiny or dull, smooth or minutely striate-tubercled.</span><!--

-->{{Treatment/Body
|phenology=Flowering Jun–Oct.
|habitat=Dry, often disturbed places, rock outcrops, sandy ground
|elevation=300-3000 m
|distribution=Alta.;B.C.;Man.;Ont.;Que.;Sask.;Yukon;Ariz.;Calif.;Colo.;Idaho;Iowa;Mich.;Minn.;Mont.;Nebr.;Nev.;N.H.;N.Mex.;N.Y.;Oreg.;S.Dak.;Utah;Vt.;Va.;Wash.;Wyo.
|discussion=<p>Five taxa that have been included in <i>Polygonum douglasii</i> (E. Murray 1982; J. C. Hickman 1984; J. T. Kartesz and K. N. Gandhi 1990) are treated here as distinct species: <i>P. austiniae</i>, <i>P. majus</i>, <i>P. nuttallii</i>, <i>P. sawatchense</i>, and <i>P. spergulariiforme</i>. Hickman noted extensive intergradation and numerous intermediate specimens among those sympatric elements, but qualitative or quantitative characters allow reliable discrimination in most cases (M. Costea and F. J. Tardif 2005), and species are here circumscribed similar to C. L. Hitchcock (1964).</p><!--
--><p>Greene described <i></i>var.<i> latifolium</i> as having leaf blades and achenes broader than those of <i></i>var.<i> douglasii</i>. C. L. Hitchcock (1964) recognized the former, but the characters used to distinguish it appear to vary continuously, and reliable separation is not possible.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Polygonum douglasii
|authority=Greene
|rank=species
|parent rank=section
|synonyms=Polygonum douglasii var. latifolium;Polygonum emaciatum;Polygonum montanum;Polygonum tenue var. commune;Polygonum tenue var. latifolium
|basionyms=
|family=Polygonaceae
|phenology=Flowering Jun–Oct.
|habitat=Dry, often disturbed places, rock outcrops, sandy ground
|elevation=300-3000 m
|distribution=Alta.;B.C.;Man.;Ont.;Que.;Sask.;Yukon;Ariz.;Calif.;Colo.;Idaho;Iowa;Mich.;Minn.;Mont.;Nebr.;Nev.;N.H.;N.Mex.;N.Y.;Oreg.;S.Dak.;Utah;Vt.;Va.;Wash.;Wyo.
|reference=None
|publication title=Bull. Calif. Acad. Sci.
|publication year=1885
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f50eec43f223ca0e34566be0b046453a0960e173/coarse_grained_fna_xml/V5/V5_1160.xml
|subfamily=Polygonaceae subfam. Polygonoideae
|genus=Polygonum
|section=Polygonum sect. Duravia
|species=Polygonum douglasii
}}<!--

-->[[Category:Treatment]][[Category:Polygonum sect. Duravia]]