View source for Helianthus decapetalus

{{Treatment/ID
|accepted_name=Helianthus decapetalus
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=2: 905. 1753
|year=1753
}}
|common_names=Thinleaf sunflower;hélianthe à dix rayons
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Helianthus trachelifolius
|authority=Miller
}}
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Helianthinae;Helianthus;Helianthus decapetalus
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Heliantheae]]</div><div class="higher-taxon"><small>subtribe</small>[[Asteraceae (tribe Heliantheae) subtribe Helianthinae]]</div><div class="higher-taxon"><small>genus</small>[[Helianthus]]</div><div class="higher-taxon"><small>species</small>[[Helianthus decapetalus]]</div></div>
|volume=Volume 21
|mention_page=page 146, 159
|treatment_page=page 158
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Perennials,</b> 60–200 cm (rhizomatous). <b>Stems</b> erect, glabrous. <b>Leaves</b> cauline; opposite (proximal or all) or alternate (distal); petioles (1–)2–5 cm; blades (green, 3-nerved distal to bases) lanceolate to ovate, 7–21 × 4–10 cm, bases rounded to cuneate (often shortly decurrent onto petioles), margins usually serrate (moderately to notably in larger leaves), abaxial faces ± scabro-hispidulous, relatively sparsely gland-dotted. <b>Heads</b> 3–6(–10). <b>Peduncles</b> 2–12 cm (not gland-dotted). <b>Invo</b>-lucres hemispheric, 12–25 mm diam. <b>Phyllaries</b> 20–25 (often reflexed), lance-linear to lanceolate, 11–16 × 2–3 mm (sometimes leaflike, longest surpassing discs by 1/2+ their lengths), (margins ciliate) apices attenuate, abaxial faces strigillose to glabrate, not gland-dotted. <b>Paleae</b> 8–10 mm, 3-toothed. <b>Ray</b> florets 8–12; laminae 20–25 mm. <b>Disc</b> florets 40+; corollas 6.5–7.2 mm, lobes yellow; anthers usually dark brown to black (rarely reddish brown), appendages dark or reddish brown. <b>Cypselae</b> 3.5–5 mm; pappi of 2 aristate scales 3–4 mm. <b>2n</b> = 34, 68.</span><!--

-->{{Treatment/Body
|phenology=Flowering summer–fall.
|habitat=Mesic to wet woodland edges
|elevation=10–1200 m
|distribution=N.B.;Ont.;Que.;Ala.;Ark.;Conn.;Del.;D.C.;Ga.;Ill.;Ind.;Iowa;Ky.;La.;Maine;Md.;Mass.;Mich.;Miss.;Mo.;N.H.;N.J.;N.Y.;N.C.;Ohio;Okla.;Pa.;R.I.;S.C.;Tenn.;Vt.;Va.;W.Va.;Wis.
|discussion=<p><i>Helianthus decapetalus</i> is sometimes confused with <i>Heliopsis helianthoides</i> because of shared habitats and superficial similarities. The tetraploid cytotype of <i>H. decapetalus</i> intergrades (and apparently hybridizes) with <i>H. strumosus</i>, particularly in the southern Appalachians; individual specimens can be difficult to place in one or the other species. In addition to morphologic differences, <i>H. decapetalus</i> usually occurs in more mesic habitats, particularly along watercourses; <i>H. strumosus</i> is found in drier sites such as roadside slopes. <i>Helianthus</i> ×multiflorus Linnaeus is a sterile hybrid, often with “doubled” heads (in which disc florets are replaced by ray florets); it is cultivated and is sometimes included within <i>H. decapetalus</i>, e.g., <i>H. decapetalus</i> <i></i></i>var.<i><i> multiflorus</i> (Linnaeus) A. Gray; its parents are <i>H. decapetalus</i> and <i>H. annuus</i>.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Helianthus decapetalus
|author=
|authority=Linnaeus
|rank=species
|parent rank=genus
|synonyms=Helianthus trachelifolius
|basionyms=
|family=Asteraceae
|phenology=Flowering summer–fall.
|habitat=Mesic to wet woodland edges
|elevation=10–1200 m
|distribution=N.B.;Ont.;Que.;Ala.;Ark.;Conn.;Del.;D.C.;Ga.;Ill.;Ind.;Iowa;Ky.;La.;Maine;Md.;Mass.;Mich.;Miss.;Mo.;N.H.;N.J.;N.Y.;N.C.;Ohio;Okla.;Pa.;R.I.;S.C.;Tenn.;Vt.;Va.;W.Va.;Wis.
|reference=None
|publication title=Sp. Pl.
|publication year=1753
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V19-20-21/V21_377.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Helianthinae
|genus=Helianthus
|species=Helianthus decapetalus
}}<!--

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