Lemna disperma
Common names
common duckweed
Biostatus
Native
Category
Vascular
Structural class
Herbs - Monocots
Flower colours
Green, Yellow
Detailed description
Platelets up to 6 x 4 mm, suborbicular to elliptic-obovate, nearly symmetric, bearing 1-2 vegetative buds per platelet; dorsal surface bright green to yellow-green, faintly 3-veined; ventral surface paler and often tinged with red or purple, flat to slightly convex. Root single, peltately attached, rather long for size of plant, proximal portion lying in a fine furrow in the platelet tissue; root-cap conspicuous. Inflorescence in lateral pouch, partly enclosed by spathe; spathe opened at apex. Ovule solitary. Fruit ovoid, wingless, projecting beyond the pouch margin. Seed obovate, flattened, smooth; operculum prominent, more or less flattened.
Similar taxa
Could only be confused with the introduced Landoltia punctata (also known as Spirodela oligorrhiza (Kurz) Hegelm) which differs by its larger size, platelets whose ventral surface is usually dark purple (rather than pale green), and which bear 2 or more (rather than one) roots.
Distribution
Indigenous. North, South, Stewart and Chatham Islands (Uncommon on Stewart and Chatham Islands). Otherwise cosmopolitan.
Habitat
Coastal to montane (up to 400 m a.s.l.). In still, fertile water usually in sunny situations (rarely in shade). Often growing intermixed with Landoltia punctata (G.Mey.) Les et D.J.Crawford, Azolla filiculoides Lam., Wolffia australiana (Benth.) Hartog et Plas, Ricciocarpos natans (L.) Corda and Riccia fluitans L.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Not Threatened
Detailed taxonomy
Family
Araceae
Synonyms
Lemna minor L. has been applied, incorrectly, for New Zealand plants
Taxonomic notes
New Zealand plants have been referred to L. minor L. which is a widespread northern hemisphere species which little resembles the New Zealand plant and may not even be here (indeed Landolt (2011) states that only L. disperma is present in New Zealand, and that L. minor is a very uncommon naturalised species in Australia). Irrespective New Zealand plants are cytologically variable and there is still some doubt as to the whether L. disperma is indeed the most appropriate name for some or all of them. Further research is needed.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
November - February
Fruiting
December - April
Propagation technique
Easily grown in a sunny site within a pond, or similar still or slowly flowing body of water. An excellent aquarium plant. However, can be invasive in some situations, especially in nutrient rich water. An important food for many invertebrates, tadpoles, fish and some dabbling birds
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
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.
LEMDIS
Chromosome number
2n = 20, 30, 42, 40
Previous conservation statuses
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Landolt, E. 2011: Lemnaceae Pp. 274-282. Flora of Australia 39. Alismatales to Arales. ABRS/CSIRO, Melbourne, Australia.
Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Government Printer, Wellington.
Attribution
Fact sheet prepared for NZPCN by P. J. de Lange 31 August 2007.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Lemna disperma Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/lemna-disperma/ (Date website was queried)