Ludwigia

Scientific name

Ludwigia L.

Common names

water primrose, false loosestrife, seedbox, primrose willow

Family

Onagraceae

Native distribution

cosmopolitan

Species commonly cultivated

Ludwigia arcuata Walter (eastern U.S.)

L. brevipes (Long) Eames (southeastern U.S.)

L. glandulosa Walter (North America)

L. helminthorrhiza (Mart) H. Hara (Mexico to Paraguay)

L. inclinata (L.f.) P.H. Raven (Central and South America)

L. longifolia (DC.) H. Hara (North and South America)

L. ovalis Miq. (South America)

L. palustris (L.) Elliot (Europe, Asia, America, Australasia)

L. peploides ssp. montevidensis (Kunth) P.H. Raven (Spreng.) P.H. Raven (Australia, America)

L. peruviana (L.) Hara (southeast U.S. to South America)

L. repens J.R. Forst. (central and southern North America)

L. sedoides (Humb.& Bonpl.) H. Hara (Central and South America)

L. uruguayensis (Cambess.) H. Hara (Central and South America)

Adventive distribution

Several Ludwigia species are introduced in various parts of the world.

Weed status

Ludwigia adscendens (L.) Hara, L. hyssopifolia (G.Don) Exell and L. octovalvis (Jacq.) Raven are serious weeds in rice in numerous countries around the world.

Habit

submersed, floating, emergent, and erect stem plant; creeping, erect or bushy

Brief description

Annual or perennial. Stems creeping, erect or ascending, rooting at lower nodes, floating stems of some species with spongy aerenchyma or inflated, white pneumatophores (e.g. L. helminthorrhiza). Leaves cauline, opposite, alternate or in floating rosette (e.g. L. sedoides); leaf blade usually entire, linear to lanceolate, ovate, or obovate; apex rounded, acute or serrate (e.g. L. sedoides); margin entire, sometimes undulate. Flowers actinomorphic, axillary, solitary or clustered, sessile or borne on short pedicel; sepals 3-7 (usually 4-5), green, and fused, often forming elongate tube; petals 3-7 (usually 4-5) or absent, yellow or white, ovoid and notched at apex. Dispersal by seed or stem fragments.

Natural habitat

all types of slow-flowing waterways and wet ground

Additional comments

A diverse genus of aquatic macrophytes with a tremendous diversity of plant form ranging from floating plants to bushes. Many species are only reliably identifiable using reproductive characters.