Utricularia geminiscapa


Utricularia: a small bladder

Common Name(s)




Brief Description

Sprawling submerged plant often floating just under the waters surface, with finely divided thread-like leaves with tiny round bladders (often black).

Flora Category

Vascular - Exotic

Structural Class

Dicotyledonous Herbs other than Composites


Restricted to Westland (Westport to Haast).


Colonises acidic shallow water in lowland bogs, fens and pakihi.


Perennial, free-floating aquatic, often smothering other submerged plants or floating just under the waters surface. Stolons filiform, sparingly branched; stems up to 60 cm long, c. 0.5 mm diam., terete, glabrous, internodes <10 mm long. Leaves 10-25 mm long, divided from base into 2 primary filiform segments, each divided into numerous secondary segments. Flowers exclusively cleistogamous in New Zealand, 10 mm long, deflexed; calyx 1.0-1.5 mm long, corolla minute or ± absent. Capsule globose, 1.3-2.2 mm long, the wall ± membranous. Seeds numerous, dorsiventrally compressed, globose, 0.4-0.5 mm diameter.

Similar Taxa

Utricularia australis(rare native species mostly in northern North Island) is superficially similar and at one time U. geminiscapa was mistakenly known as this species. The distribution ranges of these species do not currently overlap.


Summer to autumn

Flower Colours



Summer to autumn

Year Naturalised



North-eastern USA and Canada

Reason for Introduction

Likely to be accidental, possibly contaminated mining machinery

Control Techniques

Not usually controlled in New Zealand.

Life Cycle and Dispersal

Water fowl spread seed. Accidental spread.


Survives only in very wet places.


Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).

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.

Heenan, P.B.; de Lange, P.J.; Knightsbridge, P.I. (2004). Utricularia geminiscapa (Lentibulariaceae), anaturalised aquatic bladderwort in the South Island, New Zealand. NZJ Bot 24: 247-251.

Salmon, B. (2001). Carnivorous plants of New Zealand. Ecosphere Publications, Auckland. 303 pp.

This page last updated on 21 Aug 2013