View source for Parthenium

{{Treatment/ID
|accepted_name=Parthenium
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=2: 988. 1753
|year=1753
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 426. 1754
|year=1754
}}
|common_names=Feverfew
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Ambrosiinae;Parthenium
|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>[[Parthenium]]</div></div>
|etymology=Greek parthenos, virgin, or parthenion, ancient name of a plant; allusion unclear
|volume=Volume 21
|mention_page=page 8, 9
|treatment_page=page 20
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals,</b> biennials, perennials, subshrubs, or shrubs [treelets], 1–120[–400] cm. <b>Stems</b> ± erect, usually branched. <b>Leaves</b> usually cauline, sometimes in rosettes; alternate; petiolate or sessile; blades elliptic, lanceolate, linear, lyrate, oblanceolate, obovate, ovate, rounded-deltate, spatulate, sometimes (1–)2-pinnately lobed, ultimate margins entire or toothed, faces usually hairy and gland-dotted (at least the abaxial). <b>Heads</b> usually radiate, sometimes ± disciform (<i>P. alpinum</i>), usually borne in corymbiform or paniculiform arrays (in glomerules in <i>P. argentatum</i>, borne singly in <i>P. alpinum</i> and <i>P. ligulatum</i>). <b>Involucres</b> ± hemispheric [rotate], 3–8(–12+) mm diam. <b>Phyllaries</b> falling, 10(–16) in 2 series, usually distinct (partially connate in <i>P. alpinum</i>), outer 5(–8) herbaceous to scarious, inner 5–8 ± scarious to membranous. <b>Receptacles</b> flat to conic; paleae cuneate to flabelliform, scarious or membranous, distally papillate and/or fimbrillate, all or the peripheral each ± enfolding a disc floret. <b>Ray</b> (pistillate) florets 5(–8), fertile; corollas ochroleucous, tubes stout, glandular, laminae oblong to reniform or orbiculate, or ± coroniform (none in <i>P. alpinum</i>). <b>Disc</b> florets 12–60+, functionally staminate; corollas ochroleucous, funnelform, lobes 5 (filaments distinct, anthers connate). <b>Cypselae</b> (black) oblanceoloid, obovoid, or pyriform, often ± obcompressed (shed together with subtending phyllary and 2 contiguous disc florets and their investing paleae); pappi 0 (shoulders of cypselae may bear 1–3 pappus-like, triangular to ovate, or ± subulate enations). <b>x</b> = 9.</span><!--

-->{{Treatment/Body
|distribution=New World;mostly warm-temperate and tropical;some temperate;introduced in Old World.
|discussion=<p>Species ca. 16 (7 in the flora).</p>
|tables=
|references={{Treatment/Reference
|id=mears1975a
|text=Mears, J. A. 1975. The taxonomy of Parthenium section Partheniastrum DC. (Asteraceae–Ambrosiinae). Phytologia 31: 463–482.
}}{{Treatment/Reference
|id=rollins1950a
|text=Rollins, R. C. 1950. The guayule rubber plant and its relatives. Contr. Gray Herb. 172: 1–73.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Plants 1–2 cm (plants cespitose or forming mats); heads borne singly
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Plants (5–)15–120 cm (plants not cespitose or forming mats); heads in glomerules, or in simple or compound, corymbiform or paniculiform arrays
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Corollas of pistillate florets bearing laminae 1–2 mm
|[[Parthenium ligulatum|Parthenium ligulatum]]
|-id=key-0-2
|2
|Corollas of pistillate florets lacking laminae
|[[Parthenium alpinum|Parthenium alpinum]]
|-id=key-0-3
|3
|Shrubs
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Annuals, biennials, or perennials
|[[#key-0-5| > 5]]
|-id=key-0-4
|4
|Leaf blades oval-elliptic to obovate (sometimes pinnately 3–7-lobed or round-toothed, ultimate margins entire)
|[[Parthenium incanum|Parthenium incanum]]
|-id=key-0-4
|4
|Leaf blades lanceolate to oblanceolate (margins mostly entire, some with 1–5 sharp teeth)
|[[Parthenium argentatum|Parthenium argentatum]]
|-id=key-0-5
|5
|Perennials; leaf blades usually crenate to serrate, sometimes coarsely toothed or somewhat lobed (then mostly toward bases); pappus-like enations from shoulders of cypselae 0 or 2(–4), erect to spreading, ± subulate or threadlike
|[[Parthenium integrifolium|Parthenium integrifolium]]
|-id=key-0-5
|5
|Annuals or biennials (sometimes persisting); leaf blades mostly 1–2-pinnately lobed; pappus-like enations from shoulders of cypselae 2, erect, ± deltate to ovate.
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Biennials (sometimes flowering first year or persisting); leaf blades ± pinnately lobed, abaxial faces strigillose (usually with erect hairs 1–2 mm as well)
|[[Parthenium confertum|Parthenium confertum]]
|-id=key-0-6
|6
|Annuals (rarely persisting); leaf blades (1–)2-pinnately lobed, abaxial faces scabrellous (seldom with erect hairs 1–2 mm)
|[[Parthenium hysterophorus|Parthenium hysterophorus]]
|}
</div></div><!--

-->{{#Taxon:
name=Parthenium
|author=John L. Strother
|authority=Linnaeus
|rank=genus
|parent rank=subtribe
|synonyms=
|basionyms=
|family=Asteraceae
|illustrator=Linda Ann Vorobik
|distribution=New World;mostly warm-temperate and tropical;some temperate;introduced in Old World.
|reference=mears1975a;rollins1950a
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=1753;1754
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V19-20-21/V21_29.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Ambrosiinae
|genus=Parthenium
}}<!--

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