Iva

Linnaeus

Sp. Pl. 2: 988. 1753.

,

Gen. Pl. ed. 5, 426. 1754.

Common names: Marsh elder
Etymology: Etymology uncertain perhaps for Ajuga iva, a mint with similar odor
Treatment appears in FNA Volume 21. Treatment on page 25. Mentioned on page 9.
 TaxonIllustrator 
FNA21 P04 Iva frutescens.jpegIva frutescens
Iva axillaris
Cyclachaena xanthiifolia
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Marjorie C. Leggitt

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

Distribution

Mostly temperate North America, some subtropical, some in Old World

Discussion

Species ca. 9 (7 in the flora).

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.

Ivas are wind pollinated, are related to the ragweeds (Ambrosia spp.), and may be similarly associated with pollen allergies.

Records of Iva asperifolia Lessing from Florida are evidently based on specimens that are treated as members of I. angustifolia.

Selected References

None.

Key

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 > 2
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 > 4
2 Leaves petiolate, blades mostly deltate to lanceolate, margins toothed Iva annua
2 Leaves ± sessile, blades mostly lance-linear to filiform, margins entire > 3
3 Involucres ± prismatically turbinate, 2.5–3 mm; outer phyllaries ± connate Iva angustifolia
3 Involucres ± hemispheric, 1.5–2 mm; outer phyllaries distinct Iva microcephala
4 Subshrubs or shrubs, 50–350 cm; leaf blades ovate or elliptic to lanceolate, margins usually toothed Iva frutescens
4 Perennials or subshrubs, 10–50(–100) cm; leaf blades mostly obovate or elliptic to lanceolate, oblanceolate, or spatulate, margins usually entire, rarely toothed > 5
5 Leaf blades glabrous; involucres campanulate to urceolate, 5–7+ mm; cypselae 4–5 mm Iva imbricata
5 Leaf blades usually strigose to scabrellous; involucres ± hemispheric, 2–3.5 mm; cypselae 2–3 mm > 6
6 Aerial stems usually woody at bases; outer phyllaries distinct Iva hayesiana
6 Aerial stems usually herbaceous; outer phyllaries ± connate Iva axillaris
... more about "Iva"
not tailed +, rounded +  and obtuse +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
spiciform +  and racemiform +
indeterminate +  and determinate +
John L. Strother +
Linnaeus +
decurrent +
compound +  and simple +
trullate;spatulate;trullate;spatulate;ovate;obovate;linear;lanceolate;filiform;elliptic;deltate +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Marsh elder +
whitish +  and pinkish +
scabrellous +
obcompressed +, plumply obovoid +  and pyriform +
fertile +  and bisexual +
Mostly temperate North America +, some subtropical +  and some in Old World +
Etymology uncertain +  and perhaps for Ajuga iva, a mint with similar odor +
scabrellous +
staminate +  and pistillate +
winged +  and beaked +
dispersed +
disciform +  and discoid +
in corymbiform , glomerate , paniculiform , racemiform or spiciform , arrays +  and singly +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
scarious +  and membranous +
0.2 cm2 mm <br />0.002 m <br /> (1 cm10 mm <br />0.01 m <br />) +
less hemispheric or turbinate;campanulate or urceolate +
conspicuous +
sessile +  and petiolate +
deltate +
dentate to pinnatifid or palmatifid +  and entire +
toothed +  and entire +
2-carpellate +
spatulate;linear or setiform +
membranous +
persistent +
connate +  and distinct +
3 +  and 15 +
unequal +  and subequal +
Sp. Pl. +  and Gen. Pl. ed. +
1753 +  and 1754 +
bearing subulate enations +, hairy +  and bristly +
convex;hemispheric +
exalbuminous +
decumbent +  and sprawling +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Undefined (tribe Undefined) subtribe Ambrosieae +  and Undefined (tribe Undefined) subtribe Iveae +
Asteraceae (tribe Heliantheae) subtribe Ambrosiinae +
campanulate +  and cylindric +
toothed +  and entire +
perennial +  and annual +
shrub +  and subshrub +