Trithuria inconspicua - little plant of the lake floor
Trithuria inconspicua is a tiny plant, native to Aotearoa, that is only found in the sandy shallows of Northland dune lakes.
At a maximum of 55mm tall, this plant certainly lives up to its name of “inconspicua”. It lives partially buried in the sands of the lake floor, so you are more likely to feel it beneath your feet than see it. It has fans of fine, hair-like leaves in which it hides tiny flowers that look like miniature waterlilies.
Despite its small size, this remarkable plant has a big secret. The latest scientific research has revealed Trithuria inconspicua to be in the oldest flowering plant lineage. This means that Trithuria inconspicua has been growing on our planet for over 100 million years – a “living fossil”. It’s no surprise that tamariki at our dune lake education days call it the “dinosaur plant’!
Trithuria inconspicua is classified as Threatened – Nationally Critical. It is seriously threatened by introduced bladderwort (Utricularia gibba), invasive oxygen weeds, and declining water quality, and since 1998 has become extinct in 7 of the 13 lakes which once supported populations.
However, the good news is that it’s possible for populations to recover from seed in the sandy lake bed, as proved at Lake Ngatu. By 2020, water levels had dropped so significantly at Lake Ngatu there were concerns of another lake-wide extinction, however, rainfall raised the lake level and during ecological monitoring in spring 2021, Trithuria was found to have recovered and was present on all monitoring transects.
- Tiny native flowering plant of lake beds
- Maximum 55mm tall
- Found only in dune lakes in Te Taitokerau
- Threatened – Nationally Critical
- Of the oldest flowering plant lineage, over 100 million years old
How you can help
This plant is Critically Endangered. If you see it, please don’t pick it, dig it up or trample it, just leave it undisturbed. In any case it is very difficult to grow – it will not survive in your aquarium or pond at home.
Freshwater pests are already established in some of Northland’s lakes, rivers, and streams. Trithuria inconspicua is seriously threatened by introduced bladderwort and oxygen weeds.
If you visit our lakes and rivers, you can help to prevent the spread of freshwater pests by using the ‘Check Clean Dry’ method.
CHECK equipment and remove any fragments of plants or weeds
CLEAN all equipment that had been in contact with water
DRY equipment thoroughly and then wait for at least 48 hours before entering water again.