''Trithuria inconspicua'' subsp. ''brevistyla'' is a subspecies of '' Trithuria inconspicua'' in the family Hydatellaceae endemic to the

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

of New Zealand.

Description

Vegetative characteristics

It is a 10–40 mm tall,de Lange, P.J. (2024): ''Trithuria brevistyla'' Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/trithuria-brevistyla/ (2024-11-13) aquatic, perennial, rhizomatous herb with adventitious roots as well as 8–37 mm long, and 0.4–0.6 mm wide leaves.

Generative characteristics

Only female plants are known. Male reproductive structures have not been observed. The 1–5, unisexual, female reproductive units ("flowers") consist of glabrous, terete, 1–6 mm long, and 0.3–0.4 mm wide stalks, which do not elongate with maturity, 2–4(–7) ovate, 1.6–4.0 mm long involucral bracts, and 9–25 carpels with short stigmatic hairs. The globose to ovoid fruit is 0.39–0.56 mm long, and 0.3–0.5 mm wide. It is an

apomictic In botany, apomixis is asexual reproduction, asexual development of seed or embryo without Fertilisation, fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils. Apomictic ...

species. Flowering occurs from January to February and fruiting occurs from March to May.

Differentiation from ''Trithuria inconspicua'' subsp. ''inconspicua''

It differs from the autonymous subspecies ''Trithuria inconspicua'' subsp. ''inconspicua'' in respect to the morphology of the reproductive structures (stalks not elongating with maturity, short stigmatic hairs, and globose to ovoid fruitsManaaki Whenua – Landcare Research. (n.d.-a). ''Trithuria inconspicua'' Cheeseman subsp. ''inconspicua''. Flora of New Zealand. Retrieved November 13, 2024, from https://www.nzflora.info/factsheet/taxon/Trithuria-inconspicua-subsp-inconspicua.html). In addition, male reproductive structures are known from ''Trithuria inconspicua'' subsp. ''inconspicua'', whereas ''Trithuria inconspicua'' subsp. ''brevistyla'' is considered to be female only.

Distribution

It is endemic to

, New Zealand.

Taxonomy

It was published by Kerry Alison Ford in 2019.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), 1-11. The type specimen was collected by K.A.Ford and R.D.Smissen in Mary Bay, Lake Hauroko, Southland, New Zealand on the 12th of March 2015.''Trithuria inconspicua'' subsp. ''brevistyla'' , International Plant Names Index. (n.d.). Retrieved November 13, 2024, from https://www.ipni.org/n/77200751-1 ''Trithuria inconspicua'' is placed in ''Trithuria'' sect. ''Hydatella''.Iles, W. J., Rudall, P. J., Sokoloff, D. D., Remizowa, M. V., Macfarlane, T. D., Logacheva, M. D., & Graham, S. W. (2012)
Molecular phylogenetics of Hydatellaceae (Nymphaeales): Sexual‐system homoplasy and a new sectional classification.
American Journal of Botany, 99(4), 663-676.
It was elevated to the status of the separate species ''Trithuria brevistyla'' (K.A.Ford) de Lange & Mosyakin by

Peter James de Lange Peter James de Lange (born 1966) is a New Zealand botanist at Unitec Institute of Technology. He is a Fellow of the Linnean Society, and has received the New Zealand Botanical Society Allan Mere award and the Loder Cup for his botanical work. ...

and Sergei Leonidovich Mosyakin within the same year of the original publication (2019),de LANGE, P. J., & Mosyakin, S. L. (2019)
''Trithuria brevistyla'' (Hydatellaceae), a new combination for the New Zealand endemic species from the South Island.
Ukrainian Botanical Journal, 76(2), 95-100. yet there appears to be no consensus for this decision. ''Trithuria brevistyla'' (K.A.Ford) de Lange & Mosyakin is treated as a synonym of ''Trithuria inconspicua'' subsp. ''brevistyla'' K.A.Ford by several sources,''Trithuria inconspicua'' subsp. ''brevistyla'' K.A.Ford. (n.d.). WFO Plant List , World Flora Online. Retrieved November 13, 2024, from https://wfoplantlist.org/taxon/wfo-0001368143-2024-06?page=1 but others accept the designation as a separate species.

Etymology

The subspecific epithet ''brevistyla'', from the Latin ''brevis'' meaning "brief", and ''stylus'' meaning "pencil", refers to the short stigmatic hairs found in this subspecies.Manaaki Whenua – Landcare Research. (n.d.-b). ''Trithuria inconspicua'' subsp. ''brevistyla'' K.A.Ford. Flora of New Zealand. Retrieved November 13, 2024, from https://www.nzflora.info/factsheet/taxon/Trithuria-inconspicua-subsp-brevistyla.htmlManaaki Whenua – Landcare Research. (n.d.). ''Trithuria inconspicua'' subsp. ''brevistyla'' K.A.Ford. Biota of New Zealand. Retrieved November 13, 2024, from https://biotanz.landcareresearch.co.nz/scientific-names/a1a1acd8-9b4f-4a14-a384-967383749bbe

Conservation

It is classified as Nationally Endangered (E).Johnson, P. N., Lee, W. G., & Khan, S. (2022)
Wetlands of the Otago Region.
/ref> The total area of its habitat is ≤ 100 ha (1 km²).de Lange, P. J., Gosden, J., Courtney, S. P., Fergus, A. J., Barkla, J. W., Beadel, S. M., ... & Michel, P. (2024)
Conservation status of vascular plants in Aotearoa New Zealand, 2023.
New Zealand Threat Classification Series, 43.

Ecology

It occurs in lakes at depths of 0.3–2 m, where it grows in gravel, silt, and sand substrates. Rarely during dry seasons it becomes exposed above the water level.

References

{{Taxonbar, from1=Q89073078 inconspicua subsp. brevistyla Plants described in 2019 Freshwater plants Endemic flora of New Zealand