Utricularia australis is one of New Zealand's three aquatic bladderworts. Plants can attain lengths of over 2m and may have several metre-long branches. Its couplet of dichotomously branched leaves can grow up to 2.5cm long, bearing as many as 9 ovoid traps each, 0.7-2.5mm long. Plants begin growing rapidly in spring from their winter resting bugs (turions). During summer and only if the plant is large enough (over 1m long and with several branches) may it flower, although this is usually limited to just one scape per plant. The scape rises above the water to a height of 10-20cm and bears up to 8 fleshy yellow flowers 7mm wide. The flowers very rarely produce any seed! After flowering the plants continue growing until cooler temperatures and shorter daylight hours causes them to revert to the turion phase. Turions are merely very condensed growing tips surrounded by very short modified leaves.
Habitat -
Lakes, drainage ditches and large pools in peatlands and bogs, growing in still tannin stained water.
Distribution -
North Island, mainly in the upper half from Lake Taupo northwards below about 400m altitude. Also occurs in Australia, Asia, Africa and Europe.
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