Species
Utricularia geminiscapa
Etymology
Utricularia: a small bladder
Common Name(s)
bladderwort
Family
Lentibulariaceae
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
Distribution
Restricted to Westland (Westport to Haast).
Habitat
Colonises acidic shallow water in lowland bogs, fens and pakihi.
Features
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.
Flowering
Summer to autumn
Flower Colours
Yellow
Fruiting
Summer to autumn
Year Naturalised
1975
Origin
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.
Tolerances
Survives only in very wet places.
This page last updated on 21 Aug 2013