Lemna disperma
Common name
common duckweed
Synonyms
Lemna minor L. has been applied, incorrectly, for New Zealand plants
Family
Araceae
Flora category
Vascular – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Herbs - Monocots
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.
LEMMIN
Chromosome number
2n = 20, 30, 42, 40
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
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.
Features
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.
Flowering
November - February
Flower colours
Green, Yellow
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
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.
Attribution
Fact sheet prepared for NZPCN by P. J. de Lange 31 August 2007.
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.
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)