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dune marsh-elder, seacoast marsh elder, seacoast sumpweed

Piedmont Marsh elder

Habit Perennials or subshrubs, 30–50(–100) cm. Annuals, 10–70(–100) 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 0–1 mm;

blades linear to filiform, 10–35(–60) × 0.6–1.5(–3) mm, margins entire, faces ± scabrellous, gland-dotted.

Peduncles

2–7+ mm.

0.5–1 mm.

Involucres

± campanulate to urceolate, 5–7+ mm.

hemispheric, 1.5–2 mm.

Pistillate florets

2–5;

corollas 0.3–1.5 mm.

2–3+;

corollas 0.5–0.8 mm.

Phyllaries

outer 6–10 distinct, ± herbaceous.

outer 5 distinct, ± herbaceous.

Heads

in racemiform arrays.

in ± spiciform arrays.

Cypselae

4–5 mm.

1–1.5 mm.

Paleae

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

cuneiform to setiform, 1–2 mm.

Functionally

staminate florets 8–12+;

corollas 4–5 mm.

staminate florets 3–5;

corollas 1.8–2 mm.

2n

= 34.

= 32.

Iva imbricata

Iva microcephala

Phenology Flowering Jul–Oct. Flowering Sep–Nov.
Habitat Dunes, beaches, at or near tidelands Disturbed sites, moist or wet soils
Elevation 0–10 m (0–0 ft) 1–100 m (0–300 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; FL; GA; NC; SC
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 21, p. 26. FNA vol. 21, p. 28.
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. annua, I. axillaris, I. frutescens, I. hayesiana, I. imbricata
Name authority Walter: Fl. Carol., 232. (1788) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 346. (1840)
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