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dune marsh-elder, seacoast marsh elder, seacoast sumpweed

annual marsh elder, rough marsh-elder, seacoast sumpweed

Habit Perennials or subshrubs, 30–50(–100) cm. Annuals, (10–)50–100(–150+) cm.
Stems

± decumbent to erect.

erect.

Leaves

petioles 0–2 mm;

blades narrowly lance-elliptic to lanceolate or spatulate, 1–3(–6+) cm × 4–10(–20) mm, margins usually entire, rarely toothed, faces glabrous, rarely gland-dotted.

petioles 5–20(–30) mm;

blades deltate or ovate to elliptic, trullate, or lanceolate, 30–100(–150)+ × 8–45(–80) mm, margins ± toothed, faces ± scabrellous, gland-dotted.

Peduncles

2–7+ mm.

0–1 mm.

Involucres

± campanulate to urceolate, 5–7+ mm.

± hemispheric, 3–4(–5) mm.

Pistillate florets

2–5;

corollas 0.3–1.5 mm.

3–5;

corollas 0.5–1 mm.

Phyllaries

outer 6–10 distinct, ± herbaceous.

outer 3–5 distinct, ± herbaceous.

Heads

in racemiform arrays.

in ± spiciform arrays.

Cypselae

4–5 mm.

2–3 mm.

Paleae

linear to spatulate (distally dilated), 5–6 mm.

linear, 2–2.5 mm.

Functionally

staminate florets 8–12+;

corollas 4–5 mm.

staminate florets 8–12+;

corollas 2–2.5 mm.

2n

= 34.

= 34.

Iva imbricata

Iva annua

Phenology Flowering Jul–Oct. Flowering Jul–Nov.
Habitat Dunes, beaches, at or near tidelands Disturbed sites, moist soils
Elevation 0–10 m (0–0 ft) 10–500 m (0–1600 ft)
Distribution
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; VA; West Indies (Bahamas, Cuba)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CO; FL; GA; IA; IL; IN; KS; KY; LA; MA; ME; MI; MO; MS; NC; ND; NE; NM; OH; OK; PA; SC; SD; TN; TX; VA; WI; WV; Mexico (Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 21, p. 26. FNA vol. 21, p. 27.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Iva Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Iva
Sibling taxa
I. angustifolia, I. annua, I. axillaris, I. frutescens, I. hayesiana, I. microcephala
I. angustifolia, I. axillaris, I. frutescens, I. hayesiana, I. imbricata, I. microcephala
Synonyms I. annua var. caudata, I. annua var. macrocarpa
Name authority Walter: Fl. Carol., 232. (1788) Linnaeus: Sp. Pl. 2: 988. (1753)
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