https://www.nzflora.info/factsheet/Taxon/Trithuria-inconspicua-subsp-inconspicua.html
Trithuria inconspicua is morphologically similar to T. filamentosa of Tasmania, its sister species in phylogenetic analyses with an estimated divergence of 0.5 Ma 0–1.1 Ma. They share unique features in the genus such as: perennial life history (Pledge 1974), a fully aquatic habitat (Edgar 1966; Edgar 1970; Wells et al. 1998) and apomixis (Remizowa et al. 2008; Rudall et al. 2009; Smissen et al. 2019). Gruenstaeudl et al. (2017) discovered a difference in length in the plastid genomes between the two species >15 kbp and hypothesised a single expansion in the IR region.
Ford, K. A., Champion, P. D. (2019). Nymphaeales. In: Breitwieser I. & Wilton, A. D. Flora of New Zealand — Seed Plants. Fascicle 5. Manaaki Whenua Press, Lincoln.
Flora treatment available as a download here: https://www.nzflora.info/publications.html
Smissen, R.D., Ford, K.A., Champion, P.D., Heenan, P.B. (2019). Genetic variation in Trithuria inconspicua and T. filamentosa (Hydatellaceae): a new subspecies and a hypothesis of apomixis arising within a predominantly selfing lineage. Australian Systematic Botany 32: 1–11.
Smissen et al. available to download: https://www.researchgate.net/publication/330754913_Genetic_variation_in_Trithuria_inconspicua_and_T_filamentosa_Hydatellaceae_A_new_subspecies_and_a_hypothesis_of_apomixis_arising_within_a_predominantly_selfing_lineage
For a reference list on Trithuria inconspicua see Ford & Champion (2019) below:
https://www.nzflora.info/factsheet/Taxon/Trithuria-inconspicua.html
Not sure about the binomial...it´s definitely neither L. caprifolium nor L. periclymenum, though.