Ludwigia palustris
Common names
Water purslane, marsh ludwigia
Biostatus
Exotic
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Simplified description
A wetland or aquatic, and sometimes submerged perennial species. The slender stems are often reddish when submerged, and may be creeping, floating or prostrate and rooting at the nodes. The flowers are solitary, small, green and stalkless. Leaves are glossy, oval and occur in opposite pairs.
Flower colours
Green
Detailed description
Hairless herb, sometimes forming dense patches. Glossy ovate leaves up to 3 cm long. The leaves 4 x 2 cm occur in opposite pairs with submerged leaves often red to bronze in colour, petiole to about 1.5 cm long. The stems are often red in colour, creeping or floating and rooting at the nodes. The small green flowers may be tinged with red, do not have petals, but have four broad sepals, and occur in the axils of leaves. The small (4.5 by 2.5 mm) seed capsules have green ribs and the sepals persist. Seeds 0.5 mm long, in several rows.
Similar taxa
Ludwigia repens is very similar with opposite leaves and creeping habit, but can be distinguished by the yellow petalled flowers. Ludwigia peploides subsp. montevidensis and alligator weed (Alternanthera philoxeroides). Alligator weed also has opposite leaves, and L. peploides subsp montevidensis has yellow flowers and alternate leaves.
Distribution
Widespread and common in the North Island and northern and western South Island
Habitat
Still and slow flowing shallow water bodies, swamps and fens.
Conservation status
Not applicable
Detailed taxonomy
Family
Ecology
Flowering
November to April.
Year naturalised
1933
Origin
Native to North America and possibly temperate Eurasia.
Reason for introduction
Ornamental aquarium and pond plant.
Control techniques
Rarely problematic
Life cycle and dispersal
Spreads vegetatively by rooting at nodes and fragments dispersed water flow. Can also set seed.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
Etymology
palustris: From the Latin palus ‘swamp’, meaning growing in swamps
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
LUDPAL
Referencing and citations
References and further reading
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.
Aston, H (1977). Aquatic plants of Australia. Melbourne University Press, 367PP.; Popay et al (2010). An illustrated guide to common weeds of New Zealand, third edition. NZ Plant Protection Society Inc, 416pp.
Coffey BT, Clayton JS (1988). New Zealand water plants: a guide to plants found in New Zealand freshwaters. Ruakura Agricultural Cente. 65pp.
DiTomaso JM, EA Healy (2003). Aquatic and riparian weeds of the west. University of California Agriculture and Natural Resources Publication 3421, 462pp.
WSDE (2001). An aquatic plant identification manual for Washington’s freshwater plants. Washington State Department of Ecology, 195pp.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).