Utricularia gibba
NPPA pest plant
Environmental Weed (2024)
Common names
bladderwort
Biostatus
Exotic
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Simplified description
Sprawling submerged plant often floating just under the waters surface, with finely divided thread-like leaves with tiny round bladders (often black). Usually many small yellow snapdragon-like flowers are held above the water surface in summer and autumn.
Flower colours
Red/Pink, Yellow
Detailed description
Leaves are filamentous, up to 1 cm long, usually entire but occasionally branched. Bladders are up to 1.5 mm long and obliquely ovoid, situated on the leaves on short stalks. Small (c. 1 cm across) yellow flowers, with red stripes on the lower lip are commonly produced above the water surface either individually or in groups of up to 5 (8) on stems 3-20 cm long. Cleistogamous flowers are also produced on submerged stems. Capsules green, globose 2.5-3 mm across. Seed ovate, flattened with wing 0.75-1 mm x 0.7 mm.
Similar taxa
Utricularia australis(rare native species mostly in northern North Island) and U. geminiscapa (introduced species found in Westland). Utricularia gibba has entire or nearly entire leaves, whereas the other Utricularia species have leaves divided many times into filiform segments with larger bladders.
Distribution
Abundant in Northland, Auckland and northern Waikato.
Habitat
Most freshwater habitats, especially acidic and nutrient rich water.
Conservation status
Not applicable
Detailed taxonomy
Genus
Family
Endemic genus
No
Endemic family
No
Ecology
Flowering
December, January, February
Fruiting
Summer - autumn
Year naturalised
1980
Origin
Widespread and almost cosmopolitan in tropical and warm temperate countries
Reason for introduction
Originally known from northwest Auckland, possibly introduced via the aquarium trade. In late 1990’s found in Northland and likely to have been introduced from Australia via water fowl. Has rapidly spread over the past decade.
Tolerances
Tolerant of clean or nutrient-rich, warm or cold, still or slow-moving water.
Control techniques
Not usually controlled in New Zealand, but may be controlled manually, or mechanically.
Life cycle and dispersal
Perennial. Reproduces freely by seeds, turions, stem fragments. Forms dense mats. Dispersed by Water movement, dumped aquaria contents, contaminated machinery, eel nets, boats and trailers. Seed spread by water fowl.
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
utricularia: A small bladder
gibba: From the Latin gibbus ‘humped’ or ‘hunched’, meaning gibbous, i.e. very convex or tumid
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
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.
UTRGIB
Referencing and citations
References and further reading
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species.
Salmon, B. (2001). Carnivorous plants of New Zealand. Ecosphere Publications, Auckland. 303 pp.
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand Volume 4: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 pp.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).