View source for Centaurea diffusa

{{Treatment/ID
|accepted_name=Centaurea diffusa
|accepted_authority=Lamarck
|publications={{Treatment/Publication
|title=in J. Lamarck et al., Encycl.
|place=1: 675. 1785
|year=1785
}}
|common_names=Diffuse or tumble or white knapweed;centaurée diffuse
|special_status={{Treatment/ID/Special_status
|code=I
|label=Introduced
}}
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Acosta diffusa
|authority=(Lamarck) Soják
|rank=species
}}
|hierarchy=Asteraceae;Asteraceae tribe Cardueae;Centaurea;Centaurea diffusa
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Cardueae]]</div><div class="higher-taxon"><small>genus</small>[[Centaurea]]</div><div class="higher-taxon"><small>species</small>[[Centaurea diffusa]]</div></div>
|volume=Volume 19
|mention_page=page 183, 194
|treatment_page=page 190
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals </b>or perennials, 20–80 cm. <b>Stems</b> 1–several, much-branched throughout, puberulent and ± gray tomentose. <b>Leaves</b> hispidulous and ± short-tomentose; basal and proximal cauline petiolate, often absent at anthesis, blades 10–20 cm, margins bipinnately dissected into narrow lobes; mid cauline sessile, bipinnately dissected; distal much smaller, entire or pinnately lobed. <b>Heads</b> disciform, in open paniculiform arrays. <b>Involucres</b> narrowly ovoid or cylindric, 10–13 × 3–5 mm. <b>Principal</b> phyllaries: bodies pale green, ovate to lanceolate, glabrous or finely tomentose, with a few prominent parallel veins, margins and erect appendages fringed with slender stramineous spines, each phyllary tipped by spine 1–3 mm. <b>Inner</b> phyllaries lanceolate, ± acute, appendage lacerate or spine-tipped. <b>Florets</b> 25–35; corollas cream white (rarely pink or pale purple), those of sterile florets 12–13 mm, slender, inconspicuous, those of fertile florets 12–13 mm. <b>Cypselae</b> dark brown, ca. 2–3 mm; pappi 0 or less than 0.5 mm, only rudimentary. <b>2n</b> = 18, 36.</span><!--

-->{{Treatment/Body
|phenology=Flowering summer (Jun–Aug).
|habitat=Disturbed sites in grasslands, woodlands, open coniferous forests
|elevation=100–2200 m
|distribution=Alta.;B.C.;Ont.;Que.;Sask.;Yukon;Ariz.;Calif.;Colo.;Conn.;Idaho;Ill.;Ind.;Iowa;Ky.;Mass.;Mich.;Mo.;Mont.;Nebr.;Nev.;N.H.;N.J.;N.Mex.;Oreg.;R.I.;Tenn.;Utah;Wash.;Wyo.;Europe.
|introduced=true
|discussion=<p><i>Centaurea diffusa</i> is native to southeastern Europe and casually adventive in central and western Europe.</p><!--
--><p><i>Centaurea diffusa</i> readily hybridizes with <i>C. stoebe </i>subsp.<i> micranthos</i> and is often confused with their fertile hybrid (C. ×psammogena G. Gáyer); the latter can be recognized by its cypselae bearing pappi and having conspicuously radiant heads. Morphologically the hybrids are extremely variable; they may be intermediate or may closely resemble one or the other of the parents. Conspicuously radiant heads and pappi are always present; appendages of the phyllaries are brown to black, or rarely stramineous; spines are absent or short and 2n = 18. <i>Centaurea</i> ×psammogena is known from waste places, roadsides, railway tracks; 50–2500 m; B.C., Ont., Que.; Colo., Mass., Mich., Mo., N.C., Oreg., Tenn., Wash. It may occur spontaneously where the ranges of the parent species overlap; they may also be distributed separately. In mixed stands it replaces <i>C. diffusa</i> by introgression. Hybrids are often misidentified as <i>C. diffusa</i>.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Centaurea diffusa
|authority=Lamarck
|rank=species
|parent rank=genus
|synonyms=Acosta diffusa
|basionyms=
|family=Asteraceae
|phenology=Flowering summer (Jun–Aug).
|habitat=Disturbed sites in grasslands, woodlands, open coniferous forests
|elevation=100–2200 m
|distribution=Alta.;B.C.;Ont.;Que.;Sask.;Yukon;Ariz.;Calif.;Colo.;Conn.;Idaho;Ill.;Ind.;Iowa;Ky.;Mass.;Mich.;Mo.;Mont.;Nebr.;Nev.;N.H.;N.J.;N.Mex.;Oreg.;R.I.;Tenn.;Utah;Wash.;Wyo.;Europe.
|introduced=true
|reference=None
|publication title=in J. Lamarck et al., Encycl.
|publication year=1785
|special status=Introduced
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V19-20-21/V19_218.xml
|tribe=Asteraceae tribe Cardueae
|genus=Centaurea
|species=Centaurea diffusa
}}<!--

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