Trithuria filamentosa is a species of aquatic plant in the family Hydatellaceae endemic to Tasmania, Australia.
Description Vegetative characteristics It is an annual or perennial, diminutive, aquatic herbDuretto 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 with elongate, 0.7–1.5 mm wide, erect, sympodial rhizomes with adventitious roots.Sokoloff, D. D., Remizowa, M. V., Briggs, B. G., & Rudall, P. J. (2009). Shoot architecture and branching pattern in perennial Hydatellaceae (Nymphaeales). International Journal of Plant Sciences, 170(7), 869-884. The pale green, linear, acute leaves are 1-2 cm long.University of Tasmania. (n.d.). Trithuria filamentosa. Key to Tasmanian Vascular Plants. Retrieved November 6, 2024, from https://www.utas.edu.au/dicotkey/dicotkey/aquat_mono/gHydatella.htm Generative characteristics It is a monoecious species with mostly unisexual reproductive units ("flowers"), but more rarely with bisexual reproductive units.D.A.Cooke, Hydatellaceae, Flora of Australia 45: 1–5 (1987). The male reproductive units, which are fewer in number than the female ones, consist of 2–4, lanceolate, 3–5 mm long bracts, as well as 4–6 stamens. The stamens have red to purple, 2 mm long anthers, and 6 mm long filaments. The female reproductive units consist of 2–4(5) bracts, as well as up to 20 carpels. The elliptical-ovoid, fruit is indehiscent. The seeds are smooth. It may be reproducing apomictically, or may predominantly rely on self-pollination.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. Flowering and fruiting occurs from December to April.Trithuria filamentosa Rodway. (n.d.). Atlas of Living Australia. Retrieved November 6, 2024, from https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2907592#ausTraits
Cytology The chloroplast genome is 180562 bp long.Gruenstaeudl, M., Nauheimer, L., & Borsch, T. (2017). Plastid genome structure and phylogenomics of Nymphaeales: conserved gene order and new insights into relationships. Plant systematics and evolution, 303, 1251-1270.
Distribution It is endemic to Tasmania, Australia.
Taxonomy It was described by Leonard Rodway in 1897.Rodway, Leonard 1897, On Trithuria filamentosa, Papers & Proceedings of the Royal Society of Tasmania, pp. 47-48. The lectotype was collected by Rodway in Broad River, Tasmania, Australia in December 1896.Lectotype of Trithuria filamentosa Rodway [family HYDATELLACEAE]. (n.d.). JSTOR. Retrieved November 3, 2024, from https://plants.jstor.org/stable/10.5555/al.ap.specimen.nsw148485Sokoloff, 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. It is placed in the section Trithuria sect. Hydatella.
Etymology The specific epithet filamentosa, from the Latin 'filum' for thread, means thread-like.Eggli, U., & Newton, L. E. (2004). Etymological Dictionary of Succulent Plant Names. p. 83. Springer Science & Business Media.Species: Stichosiphon filamentosus. (n.d.). LPSN - List of Prokaryotic Names With Standing in Nomenclature. Retrieved November 6, 2024, from https://lpsn.dsmz.de/species/stichosiphon-filamentosus The stamens have long, filiform filaments.
Ecology It occurs in marshes, pools on mud flats along rivers, lakes, tarns, and stream margins.
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