View source for Xanthium

{{Treatment/ID
|accepted_name=Xanthium
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=2: 987. 1753
|year=1753
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 424. 1754
|year=1754
}}
|common_names=Lampourde
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Ambrosiinae;Xanthium
|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 Ambrosiinae]]</div><div class="higher-taxon"><small>genus</small>[[Xanthium]]</div></div>
|etymology=Greek xanthos, yellow, evidently alluding to an ancient name for a plant that produced a yellow dye
|volume=Volume 21
|mention_page=page 9
|treatment_page=page 19
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals </b>(coarse), 10–200+ cm. <b>Stems</b> erect, branched. <b>Leaves</b> cauline; mostly alternate (proximal 2–6 sometimes opposite); petiolate; blades lanceolate, linear, ovate, rounded-deltate, or suborbiculate, often ± palmately or pinnately lobed, ultimate margins entire or ± toothed, faces hirtellous or ± strigose, usually gland-dotted as well. <b>Heads</b> discoid, either pistillate (proximal) or functionally staminate (distal), in racemiform to spiciform arrays or borne singly (in axils). <b>Pistillate</b> heads: involucres ± ellipsoid, 2–5+ mm diam. at anthesis (6–20+ mm diam. at maturity); phyllaries 30–75+ in 6–12+ series, outer 5–8 distinct, the rest (sometimes interpreted as paleae) proximally connate, their distinct tips mostly ± hooked (the distal 1–3 usually longer, stouter, and not hooked), the whole becoming a hard, prickly perigynium (a bur); florets 2, corollas 0. <b>Staminate</b> heads: involucres ± saucer-shaped, 3–5 mm diam.; phyllaries 6–16+ in 1–2+ series, distinct to bases; receptacles conic to columnar; paleae spatulate to cuneiform or linear, membranous, distally ± villous or hirtellous; florets 20–50+, corollas whitish, ± funnelform, lobes 5, erect or reflexed (filaments connate, anthers distinct or weakly coherent). <b>Cypselae</b> (black) ± fusiform, enclosed in obovoid to ellipsoid, hard, prickly, 2-chambered burs; pappi 0. <b>x</b> = 18.</span><!--

-->{{Treatment/Body
|distribution=New World;introduced nearly worldwide.
|discussion=<p>Species 2–3 (2 in the flora).</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Nodal spines 0; leaf blades suborbiculate to ± pentagonal or deltate
|[[Xanthium strumarium|Xanthium strumarium]]
|-id=key-0-1
|1
|Nodal spines (1–)3-lobed, 15–30+ mm; leaf blades ± lanceolate to ovate or lance-linear
|[[Xanthium spinosum|Xanthium spinosum]]
|}
</div></div><!--

-->{{#Taxon:
name=Xanthium
|author=John L. Strother
|authority=Linnaeus
|rank=genus
|parent rank=subtribe
|synonyms=
|basionyms=
|family=Asteraceae
|distribution=New World;introduced nearly worldwide.
|reference=None
|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/V19-20-21/V21_26.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Ambrosiinae
|genus=Xanthium
}}<!--

-->[[Category:Treatment]][[Category:Asteraceae (tribe Heliantheae) subtribe Ambrosiinae]]