Pacific azolla, azolla, red azolla
Azolla rubra R. Br.; Azolla filiculoides var. rubra (R.Br.) Strasb.; Azolla filiculoides Lam. auct. non. N.Z. authors
Vascular – Native
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.
2n = 44
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
Indigenous. New Zealand: Kermadec (Raoul Island), North and South Islands. Widespread throughout the Pacific extending into Asia and India.
Coastal to lower montane. An aquatic plant frequenting shallow water bodies such as ponds, lake margins, dams and slow flowing streams. Also present in swamps on muddy ground. Occasionally establishing in cattle troughs. Azolla is most common in shallow eutrophic water bodies but it can also establish in more acidic wetland systems, where it is often a conspicuous plant of the lagg zone.
Aquatic, floating, dark-red (when exposed) or glaucous-green plants, usually forming ovate to ovoid patches on the surface of water bodies. Branching irregular; roots peg-like, simple (not branched). Leaves triangular; apex rounded; margins membranous, translucent; surface smooth, bright red or glaucous-green. Microsporangiate massulae spherical, surface conspicuously barbed. Megasporocarps brown, partially obscured by leaf lobe
Azolla pinnata which is presumably introduced in New Zealand (it could also have arrived naturally from Australia). Azolla pinnata is best distinguished from A. rubra by its pinnate rather than simple roots. Azolla pinnata is extremely invasive and has largely replaced A. rubra in Northland and Auckland.
Not applicable - spore producing
Not applicable - spore producing
Minute spores are dispersed by wind, water and attachment (Thorsen et al., 2009).
Easily grown (too easily!) in a pond or slow flowing stream. Plants tend to spread by fragmentation. Tolerant of shade but flourishes best in full sun. Inclined to be aggressive, especially in eutrophic water. Due to the cyanobacteria found within the plant, Azolla plants are able to fix atmospheric nitrogen. Azolla is also an important food source for the tadpole phase of the introduced Australian frogs Litoria raniformis and L. aurea
azolla: From the Greek azo ‘to dry’ and ollo ‘to kill’, killed by dryness
Azolla rubra has under gone a number of name changes over the last forty years. New Zealand plants have recently reverted back to A. rubra - for more information see Brownsey & Perrie (2013).
Description prepared by P.J. de Lange (1 August 2009). Description based on live plant material and herbarium specimens
References and further reading
Brownsey, P.J.; Perrie, L.R. 2013: Azolla rubra revisited. New Zealand Botanical Society Newsletter 111: 6-7.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 2009 Vol. 11 No. 4 pp. 285-309
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Azolla rubra Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/azolla-rubra/ (Date website was queried)