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common water-primrose, eastern false loosestrife, ludwigie palustre, marsh primrose-willow, marsh purslane, marsh seedbox, water-purslane

creeping primrose-willow, creeping water primrose, creeping waterpurslane, red ludwigia

Habit Herbs often creeping, rooting at nodes, forming mats. Herbs creeping and rooting at nodes, often forming loose mats.
Stems

prostrate or decumbent and ascending at tips, subterete or with raised lines decurrent from leaf axils, well branched, 10–50(–70) cm, glabrous or, sometimes, minutely strigillose on leaf margins and inflorescence.

prostrate, ascending to suberect at tips, terete, sparsely branched, 30–80 cm, glabrous or, sometimes, minutely strigillose on leaf margins and inflorescence.

Leaves

opposite;

stipules narrowly deltate, 0.05–0.1 × 0.05–0.1 mm;

petiole narrowly winged, 0.1–2.5 cm, blade narrowly to broadly elliptic or ovate-elliptic, 0.5–4.5 × 0.3–2.3 cm, base abruptly attenuate, margins entire and minutely strigillose, apex subacute, surfaces glabrous;

bracts not reduced.

opposite;

stipules narrowly deltate, 0.05–0.1 × 0.05–0.1 mm;

petiole narrowly winged, 0.3–2.3 cm, blade narrowly elliptic to broadly lanceolate-elliptic or suborbiculate, 0.8–4.5 × 0.4–2.7 cm, base attenuate, margins entire or sometimes with hydathodal glands, apex acute or apiculate, rarely obtuse, surfaces lustrous, subglabrous or sparingly to densely papillose strigillose;

bracts not much reduced.

Inflorescences

leafy spikes or racemes, flowers usually paired in leaf axils of prostrate stems;

bracteoles attached at base or to 2.5 mm distal to base of ovary, sublinear, 0.3–1(–1.8) × 0.1–0.8 mm.

sometimes few-flowered, erect racemes, flowers paired in leaf axils of prostrate stems;

bracteoles attached in opposite pairs to pedicel 1–5 mm proximal to base of ovary, lanceolate to narrowly oblong-lanceolate or sublinear, 1–5(–8) × 0.2–1 mm, apex acute, surfaces sparingly minutely strigillose.

Flowers

sepals ascending, green, ovate-deltate, 1.1–2 × 1–2.1 mm, margins finely serrulate with minute hairs, apex acuminate, sometimes with blunt tip, surfaces glabrous;

petals 0;

filaments translucent, 0.4–0.6 mm, anthers 0.2–0.4 × 0.3–0.6 mm;

pollen shed singly;

ovary oblong, 1.5–3.5 × 1–2 mm, glabrate;

nectary disc elevated 0.15–0.3 mm on ovary apex, green, 1–2 mm diam., 4-lobed, glabrous;

style pale green, 0.3–0.7 mm, glabrous, stigma subglobose or capitate, 0.4–0.6 × 0.2–0.4 mm, not exserted beyond anthers.

sepals ascending, light green, ovate deltate to narrowly so, 1.8–5 × 1.5–3.5 mm, margins minutely strigillose, apex acuminate to elongate-acuminate, surfaces subglabrous;

petals caducous, oblanceolate to elliptic-oblong, 1.1–3 × 0.4–1.4 mm, base attenuate, apex obtuse, often variable in size and shape in same flower;

filaments pale yellow, 0.5–1.5 mm, slightly inflated near base, anthers 0.4–0.9 × 0.3–0.8 mm;

pollen shed singly or in tetrads;

ovary obconic-cylindric, barely 4-angled to subterete, 2–6 × 2.5–3.5 mm;

nectary disc elevated 0.3–0.8 mm on ovary apex, yellow, 1.1–3 mm diam., 4-lobed, glabrous;

style pale yellow, 0.6–0.9 mm, glabrous, stigma pale yellow, broadly capitate, 0.3–0.5 × 0.3–0.8 mm, usually not exserted beyond anthers.

Capsules

oblong obovoid, 4-angled, (1.6–)2–5 × 1.5–3(–3.5) mm, thin-walled, irregularly dehiscent or dispersing as unit, pedicel 0–0.5 mm.

elongate-obpyramidal, 4-angled, corners sometimes rounded, 4–10 × 2.5–4 mm, hard-walled, irregularly dehiscent, pedicel 0.1–3 mm.

Seeds

yellowish brown, ellipsoid, 0.5–0.7 × 0.3–0.4 mm, surface cells transversely elongate.

yellowish brown, ellipsoid, 0.6–0.8 × 0.3–0.5 mm, surface cells transversely elongate.

2n

= 16.

= 48.

Ludwigia palustris

Ludwigia repens

Phenology Flowering Feb–Oct.
Habitat Roadside ditches, wet meadows, dried pond bottoms, margins of ponds, swamps, rivers, alluvial sand bars.
Elevation 0–1000[–2700] m. (0–3300[–8900] ft.)
Distribution
from FNA
AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; BC; NB; NF; NS; ON; QC; Mexico (Chiapas, Chihuahua, Guerrero, Hidalgo, Jalisco, México, Michoacán, Morelos, Nuevo León, Oaxaca, San Luis Potosí, Sinaloa, Sonora, Tamaulipas, Veracruz); West Indies (Cuba, Hispaniola, Jamaica, Puerto Rico); Bermuda; Central America (Costa Rica, Guatemala, Panama); South America (Colombia, Peru, Venezuela); Europe; sw Asia; Africa; intro­duced in Pacific Islands (Hawaii, New Zealand); Australia
[WildflowerSearch map]
[BONAP county map]
from USDA
[WildflowerSearch map]
[BONAP county map]
Discussion

Ludwigia palustris is a common diploid and most widely distributed species in sect. Isnardia. It is particularly widespread in temperate North America and in Europe [the type is thought to be from Europe (P. H. Raven 1963[1964]; C. I. Peng et al. 2005)], more sporadically in Africa and sw Asia, and introduced in Australasia, and Hawaii. The close sister relationship of sect. Isnardia with sect. Miquelia (L. ovalis Miquel only, endemic to eastern Asia) suggests that this clade may have had a history connected with the evolution of the Arcto-Tertiary Geoflora (P. H. Raven and D. I. Axelrod 1974; Peng et al.).

Ludwigia palustris is known to hybridize with L. brevipes producing the sterile L. ×lacustris Eames.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Flowers Mar–Nov (year-round). Muddy or damp, sandy edges of pools, lakes, swamps, creeks, and roadside ditches, moist soil in solution pits in limerock and hammock clearings in Florida Everglades, shade or sun; 0–1200[–1600] m; Ala., Ariz., Calif., Fla., Ga., Kans., La., Miss., Nev., N.J., N.Mex., N.C., Okla., Oreg., S.C., Tenn., Tex., Va.; Mexico (Chihuahua, Coahuila, México, Morelos, Nuevo León, Puebla, San Luis Potosí, Sonora); West Indies (Bahamas, Cuba, Hispaniola, Jamaica); Bermuda; introduced in Asia (Bangladesh, Japan).

Ludwigia repens occurs primarily on the Atlantic and Gulf coastal plains of the United States from North Carolina to Texas, with more scattered distribution into west Texas, New Mexico, Oklahoma, and Kansas, and disjunct populations in New Jersey, Tennessee, southern Arizona, Nevada, California, and western Oregon (Marion County); it also occurs in northern and central Mexico and the Caribbean region. In some parts of this wide range it is considered an aquatic weed.

Ludwigia repens is one of the most popular species of Ludwigia used in the aquarium trade; this may help to account for its wide distribution.

Much like the related diploid Ludwigia palustris, the hexaploid L. repens is widespread and morphologically variable, and infraspecific taxa have been proposed to describe this variation. Given the tendency of species in sect. Isnardia to hybridize, and the lack of a geographical basis for much of the variation, C. I. Peng (1989) declined to adopt any infraspecific classification, and this treatment follows Peng.

As described in C. I. Peng et al. (2005), Ludwigia repens J. R. Forster was conserved with a new type (the original type selected was from Virginia, where the species does not occur); L. repens Swartz (1797) was a later homonym described from Jamaica and pertains here.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia
Sibling taxa
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. decurrens, L. erecta, L. glandulosa, L. grandiflora, L. hexapetala, L. hirtella, L. lanceolata, L. leptocarpa, L. linearis, L. linifolia, L. maritima, L. microcarpa, L. octovalvis, L. peploides, L. peruviana, L. pilosa, L. polycarpa, L. ravenii, L. repens, L. simpsonii, L. spathulata, L. sphaerocarpa, L. suffruticosa, L. virgata
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. decurrens, L. erecta, L. glandulosa, L. grandiflora, L. hexapetala, L. hirtella, L. lanceolata, L. leptocarpa, L. linearis, L. linifolia, L. maritima, L. microcarpa, L. octovalvis, L. palustris, L. peploides, L. peruviana, L. pilosa, L. polycarpa, L. ravenii, L. simpsonii, L. spathulata, L. sphaerocarpa, L. suffruticosa, L. virgata
Synonyms Isnardia palustris, I. ascendens, I. nitida, I. palustris var. americana, L. apetala, L. nitida, L. palustris var. americana, L. palustris var. inundata, L. palustris var. liebmannii, L. palustris var. nana, L. palustris var. pacifica Isnardia intermedia, I. natans, I. repens, I. repens var. rotundata, L. fluitans, L. natans, L. natans var. rotundata, L. natans var. stipitata, L. repens var. rotundata, L. repens var. stipitata
Name authority (Linnaeus) Elliott: Sketch Bot. S. Carolina 1: 211. (1817) J. R. Forster: Fl. Amer. Sept., 6. (1771) — (as Ludvigia), name conserved
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