''Ludwigia decurrens'' is a species of flowering plant in the evening primrose family known by the common names willow primrose and wingleaf primrose-willow. It is native to the central and eastern United States. This species is an annual herb that reaches up to tall, sometimes growing as a perennial by virtue of its partially woody stem. It has an erect form and a winged stem that is angled. The plant is

glabrous Glabrousness (from the Latin '' glaber'' meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part of ...

. The linear leaves are alternately arranged. The sessile leaves are

decurrent ''Decurrent'' (sometimes decurring) is a term used in botany and mycology to describe plant or fungal parts that extend downward. In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petio ...

: they extend down along the stem at their bases. The flower has four yellow petals. The seed capsules may contain up to 1000 seeds per capsule. This plant grows in wet habitat types, often alongside ''

Polygonum ''Polygonum'' is a genus of about 130 species of flowering plant in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass (though the common names may refer more broadly to plants from Polygonaceae). In the ...

'' and ''

Cyperus ''Cyperus'' is a large genus of about 700 species of sedges, distributed throughout all continents in both tropical and temperate regions. Description They are annual or perennial plants, mostly aquatic and growing in still or slow-moving ...

'' species. ''L. decurrens'' has become an invasive species in Africa and in Southeast Asia, where it frequently colonizes rice paddies and other wetlands. Invasion in anaerobic habitats is facilitated by the

aerenchyma Aerenchyma or aeriferous parenchyma or lacunae, is a modification of the parenchyma to form a spongy tissue that creates spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and th ...

that enable willow primrose rhizomes to float and by its capacity to spread either by seed or by vegetative propagation from broken plant fragments. Exudates from this species have been shown to have allelopathic effects on ''

Corchorus olitorius Jute mallow or nalta jute (''Corchorus olitorius'', also known as " Jew's mallow", "tossa jute", "bush okra", "krinkrin", "etinyung", " Mulukhiyah", Ademe (Adémé, in Togo) and "West African sorrel", among many other local names, often invoking t ...

'' by increasing mortality of seedlings.

References

decurrens Flora of the United States {{Myrtales-stub