Trithuria submersa is a species of plant in the family Hydatellaceae endemic to the Australian states New South Wales, South Australia, Tasmania, Victoria, and Western Australia.
Description
Vegetative characteristics It is a 8 cm tall, and 2-5 cm wide,D.A.Cooke. Trithuria submersa, in (ed.), Flora of Australia. Australian Biological Resources Study, Department of Climate Change, Energy, the Environment and Water: Canberra. https://profiles.ala.org.au/opus/foa/profile/Trithuria%20submersa [Date Accessed: 13 November 2024] annual herb with glabrous, red, 15–40(–50)Royal Botanic Gardens Victoria. (2014, January 25). Trithuria submersa Hook.f. VicFlora Flora of Victoria. Retrieved November 12, 2024, from https://vicflora.rbg.vic.gov.au/flora/taxon/4b0fcf12-f7e0-4caa-9529-50b0f77be40c mm long, and up to 1 mm wide leavesRoyal Botanic Gardens and Domain Trust, Sydney. (n.d.). Trithuria submersa Hook.f. PlantNET (the NSW Plant Information Network System). Retrieved November 12, 2024, from https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Trithuria~submersa and fibrous roots.Duretto MF (2011) 1 Hydatellaceae, 2011:1. In MF Duretto (Ed.) Flora of Tasmania Online. 4 pp. (Tasmanian Herbarium, Tasmanian Museum & Art Gallery: Hobart). www.tmag.tas.gov.au/floratasmania Individuals growing submerged in water are slender and green in colour. Generative characteristics It is a monoecious species with emergent, bisexual reproductive units ("flowers"). The several 2–3 mm wide reproductive units consist of (5–)10–32(–40) mm long stalks, (2–)4–8Sokoloff, D. D., Remizowa, M. V., Macfarlane, T. D., & Rudall, P. J. (2008). Classification of the early‐divergent angiosperm family Hydatellaceae: One genus instead of two, four new species and sexual dimorphism in dioecious taxa. Taxon, 57(1), 179-200. ovate to lanceolate, 2–4 mm long bracts, 10–20(–35) carpels with 3-6 stigmatic hairs, and 2–4 central stamens with 2 mm long red filaments and purple anthers, which are 0.6 mm long. The three-ribbed, obovoid, 0.5–0.8 mm long fruit bears sculptured, brown, 0.5 mm long, and 0.3 mm wide seeds. It is a self-pollinating species.Taylor, M. L., Macfarlane, T. D., & Williams, J. H. (2010). Reproductive ecology of the basal angiosperm Trithuria submersa (Hydatellaceae). Annals of Botany, 106(6), 909-920. Flowering and fruiting occurs from September to January.Trithuria submersa Hook.f. (n.d.). Atlas of Living Australia. Retrieved November 12, 2024, from https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/7022449 Seed germination occurs in winter, once the seasonally dry habitat becomes wet.Moschin, S., Nigris, S., Offer, E., Babolin, N., Chiappetta, A., Bruno, L., & Baldan, B. (2024). Reproductive development in Trithuria submersa (Hydatellaceae: Nymphaeales): the involvement of AGAMOUS-like genes. Planta, 260(5), 1-13. Cytology The diploid chromosome count is 2n = 56.Kynast, R. G., Joseph, J. A., Pellicer, J., Ramsay, M. M., & Rudall, P. J. (2014). Chromosome behavior at the base of the angiosperm radiation: Karyology of Trithuria submersa (Hydatellaceae, Nymphaeales). American Journal of Botany, 101(9), 1447–1455. http://www.jstor.org/stable/43826701
Taxonomy It was published by Joseph Dalton Hooker in 1858. The lectotype was collected by R.C. Gunn in Macquarie River, Tasmania, Australia on the 6th of November 1845. It is the type species of its genus. It is placed in Trithuria sect. Trithuria.Sokoloff, D. D., Remizowa, M. V., Macfarlane, T. D., Conran, J. G., Yadav, S. R., & Rudall, P. J. (2013). Comparative fruit structure in Hydatellaceae (Nymphaeales) reveals specialized pericarp dehiscence in some early–divergent angiosperms with ascidiate carpels. Taxon, 62(1), 40-61.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. Etymology The specific epithet submersa, meaning "underwater", refers to the species aquatic habitat.Government of South Australia Department for Environment and Water & Botanic Gardens of South Australia. (n.d.). Trithuria submersa (Hydatellaceae). Seeds of South Australia. Retrieved November 12, 2024, from https://spapps.environment.sa.gov.au/SeedsOfSA/speciesinformation.html?rid=4619
Distribution It is endemic to the Australian states New South Wales, South Australia, Tasmania, Victoria, and Western Australia.
Conservation Under the Threatened Species Protection Act 1995, it is classified as rare.Threatened Species Section (2024). submerged watertuft (Trithuria submersa): Species Management Profile for Tasmania's Threatened Species Link. Department of Natural Resources and Environment Tasmania. Accessed on 12/11/2024.
Ecology It occurs in temporary pools, at the edge of streams, and seasonal swamps.Western Australian Herbarium & Department of Biodiversity, Conservation and Attractions. (n.d.-c). Trithuria submersa Hook.f. Florabase—the Western Australian Flora. Retrieved November 12, 2024, from https://florabase.dbca.wa.gov.au/browse/profile/1141
References