View source for Iva

{{Treatment/ID
|accepted_name=Iva
|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=Marsh elder
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Ambrosiinae;Iva
|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>[[Iva]]</div></div>
|etymology=Etymology uncertain; perhaps for Ajuga iva, a mint with similar odor
|volume=Volume 21
|mention_page=page 9
|treatment_page=page 25
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals,</b> perennials, subshrubs, or shrubs, 10–350 cm. <b>Stems</b> usually erect, sometimes decumbent to sprawling, often freely branched. <b>Leaves</b> cauline; mostly opposite (distal sometimes alternate); petiolate or sessile; blades (1- or 3-nerved) deltate, elliptic, filiform, lanceolate, linear, obovate, ovate, spatulate, or trullate, margins entire or toothed, faces glabrous or ± scabrellous, often gland-dotted. <b>Heads</b> discoid or ± disciform, in (± bracteate) racemiform or spiciform arrays (heads 1–2 in axil of each bract, bracts sometimes leaflike). <b>Involucres</b> ± hemispheric or turbinate to campanulate or urceolate, 2–10+ mm diam. <b>Phyllaries</b> persistent, 3–15+ in 1–3+ series, distinct or ± connate, all ± herbaceous or inner scarious to membranous. <b>Receptacles</b> flat or convex to hemispheric; paleae cuneiform or spatulate to linear or setiform, ± membranous, sometimes all or partially wanting. <b>Pistillate</b> florets usually 1–8+, rarely 0; corollas whitish (inconspicuous), ± tubular. <b>Functionally</b> staminate florets 3–20+; corollas whitish to pinkish, funnelform, lobes 5, soon reflexed (filaments ± connate, anthers coherent or distinct). <b>Cypselae</b> plumply obovoid to pyriform, often ± obcompressed, sometimes scabrellous or hispidulous distally, usually ± gland-dotted; pappi 0. <b>x</b> = 18.</span><!--

-->{{Treatment/Body
|distribution=Mostly temperate North America;some subtropical;some introduced in Old World.
|discussion=<p>Species ca. 9 (7 in the flora).</p><!--
--><p>M. Bolick (1983), P. O. Karis (1995), and B. Miao et al. (1995, 1995b, 1995c) considered Iva in the sense of R. C. Jackson (1960) to include species that have closer relatives outside Iva in the broad sense than within. I agree and treat the extradited species in Chorisiva, Cyclachaena, Hedosyne, Leuciva, and Oxytenia.</p><!--
--><p>Ivas are wind pollinated, are related to the ragweeds (Ambrosia spp.), and may be similarly associated with pollen allergies.</p><!--
--><p>Records of Iva asperifolia Lessing from Florida are evidently based on specimens that are treated as members of I. angustifolia.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Annuals (seldom persisting); leaf blades deltate, filiform, lanceolate, lance-linear, or ovate (rarely succulent or fleshy); heads in ± spiciform arrays; peduncles mostly 0.5–1 mm
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Perennials, subshrubs, or shrubs; leaf blades elliptic, lanceolate, oblanceolate, obovate, ovate, or spatulate (usually ± succulent or fleshy); heads in ± racemiform arrays; peduncles mostly 1–7 mm
|[[#key-0-4| > 4]]
|-id=key-0-2
|2
|Leaves petiolate, blades mostly deltate to lanceolate, margins toothed
|[[Iva annua|Iva annua]]
|-id=key-0-2
|2
|Leaves ± sessile, blades mostly lance-linear to filiform, margins entire
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Involucres ± prismatically turbinate, 2.5–3 mm; outer phyllaries ± connate
|[[Iva angustifolia|Iva angustifolia]]
|-id=key-0-3
|3
|Involucres ± hemispheric, 1.5–2 mm; outer phyllaries distinct
|[[Iva microcephala|Iva microcephala]]
|-id=key-0-4
|4
|Subshrubs or shrubs, 50–350 cm; leaf blades ovate or elliptic to lanceolate, margins usually toothed
|[[Iva frutescens|Iva frutescens]]
|-id=key-0-4
|4
|Perennials or subshrubs, 10–50(–100) cm; leaf blades mostly obovate or elliptic to lanceolate, oblanceolate, or spatulate, margins usually entire, rarely toothed
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Leaf blades glabrous; involucres campanulate to urceolate, 5–7+ mm; cypselae 4–5 mm
|[[Iva imbricata|Iva imbricata]]
|-id=key-0-5
|5
|Leaf blades usually strigose to scabrellous; involucres ± hemispheric, 2–3.5 mm; cypselae 2–3 mm
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Aerial stems usually woody at bases; outer phyllaries distinct
|[[Iva hayesiana|Iva hayesiana]]
|-id=key-0-6
|6
|Aerial stems usually herbaceous; outer phyllaries ± connate
|[[Iva axillaris|Iva axillaris]]
|}
</div></div><!--

-->{{#Taxon:
name=Iva
|author=John L. Strother
|authority=Linnaeus
|rank=genus
|parent rank=subtribe
|synonyms=
|basionyms=
|family=Asteraceae
|distribution=Mostly temperate North America;some subtropical;some introduced in Old World.
|reference=None
|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/9216fc802291cd3df363fd52122300479582ede7/coarse_grained_fna_xml/V19-20-21/V21_41.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Ambrosiinae
|genus=Iva
}}<!--

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