[1][10] Based on molecular data from a single plastid gene (rbcL)T. inconspicua was originally believed to a monocot.

[11] However, a more recent study using multiple genetic loci, supported by a subsequent re-evaluation of morphological characteristics, now places T. inconspicua as a sister group with the water lilies (Nymphaeales).

[12] This new placement of T. inconspicua means only a single lineage of flowering plant is thought to be older, that being the woody New Caledonian shrub Amborella trichopoda.

[13] The predominant view that Amborella represents the oldest flowering plant was recently challenged in a study by Goremykini et al (2013),[14] who showed that when highly variable sites were removed from the dataset, T. inconspicua was consistently identified as the oldest angiosperm lineage.

[15][16][17] Trithuria inconspicua is seriously threatened[1] due to the competition by the introduced bladder wort (Utricularia gibba) as well as other fresh water weeds.