View source for Conyza

{{Treatment/ID
|accepted_name=Conyza
|accepted_authority=Lessing
|publications={{Treatment/Publication
|title=Syn. Gen. Compos.,
|place=203. 1832
|year=1832
}}
|common_names=Horseweed
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Astereae;Conyza
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Astereae]]</div><div class="higher-taxon"><small>genus</small>[[Conyza]]</div></div>
|etymology=Ancient name for fleabane; perhaps from Greek konops, flea, or konis, dust, alluding to powdered dry plant being used to repel insects
|volume=Volume 20
|mention_page=page 3, 9, 11, 36, 257, 349
|treatment_page=page 348
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals </b>[perennials], 10–120(–350+) cm. <b>Stems</b> usually erect, branched mostly distally (spreading and branched throughout in <i>C. ramosissima</i>), glabrous or hispid, hispidulous, strigillose, or strigose. <b>Leaves</b> basal and cauline (mostly cauline at flowering); alternate; petiolate or sessile; blades mostly lanceolate to oblanceolate or linear, margins rarely lobed, ultimate toothed or entire, faces usually hispid, hispidulous, strigillose, or strigose (eglandular). <b>Heads</b> radiate or disciform, usually in spreading to strict, paniculiform or corymbiform arrays (borne ± singly in <i>C. ramosissima</i>). <b>Involucres</b> ± turbinate, 2–5[–7+] mm diam. <b>Phyllaries</b> 20–40+ in 2–4 series, appressed (usually reflexed in fruit), the larger usually 3-nerved (midnerves orange to brownish; not notably keeled), lanceolate to linear, unequal, ± herbaceous medially, margins membranous, abaxial faces glabrous or hirsutulous, hispidulous, or strigose. <b>Receptacles</b> ± flat, pitted or smooth, epaleate. <b>Peripheral</b> (“ray”) florets pistillate, fertile: either 20–45+ in 1–2+ series, corollas white to purplish (filiform with laminae filiform to elliptic, 0.1–1[–1.5+] mm), or 20–150+ in 2–5+ series, corollas ochroleucous (filiform, laminae lacking, distally truncate or 2–5-toothed). <b>Disc</b> florets 3–30+, bisexual, fertile; corollas yellowish (nerves sometimes prominently resinous), tubes shorter than narrowly funnelform throats, lobes 5, erect or spreading, deltate; style-branch appendages deltate. <b>Cypselae</b> compressed, oblong to elliptic, 1-nerved on each edge, faces glabrous or strigillose (hairs 0.05–0.1+ mm), eglandular; pappi persistent, of 15–25+ pinkish, sordid, tawny, or white, ± equal, barbellulate, apically attenuate bristles in 1 series. <b>x</b> = 9.</span><!--

-->{{Treatment/Body
|distribution=Widespread;mostly in subtropical and warm-temperate zones.
|discussion=<p>Species 25–40+ (4 in the flora).</p><!--
--><p>Distinctions between <i>Conyza</i> and <i>Erigeron</i>, as usually circumscribed in the past 50+ years, are not always clear. Usually, conyzas have unequal (graduated) phyllaries and 2–20+ times as many pistillate florets as bisexual florets in each head (rarely more bisexual than pistillate), and corollas of pistillate florets either lack laminae or have laminae usually less than 1(–1.5) mm. Erigerons usually have subequal phyllaries and more bisexual than pistillate florets (rarely more pistillate than bisexual) and corollas of pistillate florets (if any) usually have laminae 2–10+ mm.</p><!--
--><p>In studies by R. D. Noyes (2000) and by Noyes and L. H. Rieseberg (1999), <i>Conyza</i>, as traditionally circumscribed, was found to be nested within <i>Erigeron</i> and to be para- and/or polyphyletic. Here, absent an alternate taxonomy, four species traditionally treated in <i>Conyza</i> are retained in <i>Conyza</i> and a separate suite of six species that have usually been included in <i>Conyza</i> are treated in <i>Laënnecia</i>.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Plants spreading, 5–25 cm, branched throughout (stems usually ± strigose); receptacles 0.7–1 mm diam. in fruit
|[[Conyza ramosissima|Conyza ramosissima]]
|-id=key-0-1
|1
|Plants erect, (10–)30–350+ cm, branched mostly distally; receptacles 1–5 mm diam. in fruit
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Phyllaries usually hispidulous or strigose; receptacles 3–5 mm diam. in fruit; pistillate florets 60–150+; pappi 3–4+ mm
|[[Conyza bonariensis|Conyza bonariensis]]
|-id=key-0-2
|2
|Phyllaries glabrous or sparsely strigose; receptacles 1–3 mm diam. in fruit; pistillate florets 20–45+; pappi 2–3 mm
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Phyllaries usually sparsely strigose; corollas of pistillate florets with laminae 0 or to 0.3 mm; cypselae pale tan (usually some in each head with reddish nerves)
|[[Conyza floribunda|Conyza floribunda]]
|-id=key-0-3
|3
|Phyllaries usually glabrous, sometimes sparsely strigose; corollas of pistillate florets with laminae 0.3–1+ mm; cypselae uniformly pale tan to light gray-brown
|[[Conyza canadensis|Conyza canadensis]]
|}
</div></div><!--

-->{{#Taxon:
name=Conyza
|author=John L. Strother
|authority=Lessing
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Asteraceae
|illustrator=Yevonn Wilson-Ramsey
|illustration copyright=Flora of North America Association
|distribution=Widespread;mostly in subtropical and warm-temperate zones.
|reference=None
|publication title=Syn. Gen. Compos.,
|publication year=1832
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/eaa6e58056e40c9ef614d8f47aea294977a1a5e9/coarse_grained_fna_xml/V19-20-21/V20_802.xml
|tribe=Asteraceae tribe Astereae
|genus=Conyza
}}<!--

-->[[Category:Treatment]][[Category:Asteraceae tribe Astereae]]