Flora of the Hawaiian Islands
Dicotyledon Literature for Ludwigia palustris
Peng et al., 2005.
   Onagraceae -- The Evening Primrose Family Bibliography
      Ludwigia palustris

Common name(s): false loosestrife, water primrose, marsh purslane
General Information
DistributionWidespread in North America, along the eastern seaboard from Newfoundland and Quebec, Canada, to Florida and west to eastern Minnesota, central Nebraska, and central Texas. This species also occurs along the Pacific coast from Vancouver Island, British Columbia, Canada, to southern California, with scattered occurrences in extreme southern Arizona and west Texas. In Mexico, L. palustris occurs from Chihuahua, Nuevo León, Tamaulipas, and San Luis Potosi south to Michoacan, Veracruz, and Chiapas. Ludwigia palustris also extends through Guatemala and Costa Rica in Central America to Colombia and Venezuela in South America. In the Caribbean, this species has been found in Cuba, Jamaica, Haiti, Dominican Republic, and Puerto Rico. In Eurasia, it occurs most commonly in western Europe (Raven, 1963a), from southern England, France, Portugal, and Spain eastward through the Netherlands, Belgium, Germany, Switzerland, Italy, Corsica, Austria, Poland, Czech Republic, Slovakia, Hungary, Croatia, Yugoslavia, Macedonia, Montenegro, Albania, Greece, Romania, and Bulgaria. It also occurs more sporadically to the Ukraine, the Caucasus region in Georgia, Anatolia in Turkey, and northern Iran. In Africa it occurs in coastal Morocco, Algeria, Tunisia, Socotra, southern Angola, Barotseland, Botswana, Namibia, Zimbabwe, and the Republic of South Africa (Raven, 1963a). It is introduced in the Hawaiian Islands, in New Zealand, and more recently in northeastern Victoria, Australia (Aston, 1967, 1973).In the Hawaiian Islands, naturalized on Kaua`i, O`ahu, Moloka`i, Maui, Hawai`i.

Perennial herbs with prostrate or ascending stems, rooting at the nodes, up to 50 cm or longer, well branched and forming mats.
Leaves 0.55-0.45 cm long, 0.25-0.23 cm, narrowly to broadly elliptic or ovate elliptic, glabrous, margin entire and minutely strigillose, hairs 0.05-0.1 mm long, apex subacute, base abruptly attenuated into narrowly winged petioles 1.2-25 mm long, bracteoles minute, 0.25-1(-1.8) mm long, 0.05-0.8 mm wide, ± linear, flanking ovary base or attached up to 2.5 mm above base, sometimes on very short pedicels.
Flowers axillary and usually paired, sepals green, ovate deltate, 1.1-2 mm long, 1-2.1 mm wide, ascending, glabrous, apex acuminate, sometimes with a blunt tip, margin finely serrulate and minutely strigillose, the hairs 0.02-0.05 mm long, petals absent, anthers 0.2-0.4 mm long, 0.3-0.6 mm wide, staminal filaments translucent, 0.4-0.6 mm long, pollen shed singly, nectary disc green, elevated 0.15-0.3 mm on ovary apex, 1-2 mm across, 4-lobed, glabrous, style pale green, 0.35-0.7 mm long, glabrous, stigma whitish, subglobose, 0.2-0.4 mm across.
Capsule irregularly dehiscent, (1.6-)2-5 mm long, 1.5-3(-3.5) mm in diameter, oblong obovoid or oblong with abruptly constricted base, minutely strigillose, the hairs ca. 0.05 mm long, with a green, longitudinal band 0.4-1 mm wide on the central part of each side of the capsule, representing the thinnest part of the fruit wall, obscurely 4-angled, dull light brown, subsessile or with pedicels up to 0.5 mm long.
Seeds numerous, pluriseriate and free, 0.5-0.7 mm long, 0.3-0.35 mm wide, ellipsoid, yellowish-brown, the surface cells transversely elongate, with inconspicuous raphe.
Gametic chromosome number: n = 8.