Trithuria occidentalis

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Trithuria occidentalis
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Order: Nymphaeales
Family: Hydatellaceae
Genus: Trithuria
Section: Trithuria sect. Trithuria
Species:
T. occidentalis
Binomial name
Trithuria occidentalis
Western Australia in Australia.svg
Trithuria occidentalis is endemic to Western Australia [2]
Synonyms [2]
  • Juncella occidentalis (Benth.) Hieron.
  • Hydatella dioica D.A.Cooke

Trithuria occidentalis is a species of plant in the family Hydatellaceae endemic to Western Australia. [2]

Contents

Description

Vegetative characteristics

It is an annual, [3] [1] 2-3 cm tall, aquatic herb with 2-3 cm long, and 1 mm wide, red, linear leaves. [4] The midveins of the leaves are prominent. [3]

Generative characteristics

It is a dioecious species with unisexual reproductive units. It exhibits sexual dimorphism in respect to the number of bracts present in the reproductive units ("flowers"). [5] The male reproductive units consist of 3 mm long, erect stalks with 2 lanceolate, 7-8 mm long bracts, as well as 8-10 stamens. The stamens consist of linear, 3 mm long, faintly yellow anthers, and 1 cm long filaments. [3] The female plants produce smaller reproductive units [4] with 8–9(–12) [5] 1.5-2.2mm long bracts enclosing 8-10 carpels. [4] The dehiscent fruit [5] bears seeds, which are sculptured. [4] [5]

Distribution

It is endemic to Western Australia, [2] where it is restricted to a small area north-east from Perth. [5]

Taxonomy

Trithuria occidentalis Benth. was first described by George Bentham in 1878. Later synonyms include Juncella occidentalis (Benth.) Hieron. and Hydatella dioica D.A.Cooke. [2] The type specimen was collected by James Drummond [5] [4] [6] in Swan River, Western Australia. [5] It is placed in Trithuria sect. Trithuria. [7] [8] The description of Hydatella dioica D.A.Cooke was based on a male individual of Trithuria occidentalis Benth. [5] [9]

Etymology

The specific epithet occidentalis means western. [10] [11]

Conservation

It is a threatened species. [12] Under the Western Australian Wildlife Conservation Act of 1950, it is declared as Rare Flora. According to the IUCN criteria, it is classified as Critically Endangered (CR). [4] It is classified as endangered both under the Environment Protection and Biodiversity Conservation Act 1999 and the Biodiversity Conservation Act 2016. [13] [1] In 1982, about 1000 plants were recorded. By 2007, the number of recorded individuals had dropped below 200 plants. [4]

Ecology

It occurs in seasonal swamps, [3] and shallow, winter-wet claypans. [4]

References

  1. 1 2 3 Trithuria occidentalis Benth. (n.d.). Atlas of Living Australia. Retrieved November 10, 2024, from https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2919853
  2. 1 2 3 4 5 6 "Trithuria occidentalis Benth". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 9 November 2024.
  3. 1 2 3 4 D.A.Cooke. Hydatella dioica, 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/Hydatella%20dioica [Date Accessed: 10 November 2024]
  4. 1 2 3 4 5 6 7 8 Department of Environment and Conservation (2012) Western Trithuria (Trithuria occidentalis) Interim Recovery Plan 2012–2017. Interim Recovery Plan No. 327. Department of Environment and Conservation, Western Australia.
  5. 1 2 3 4 5 6 7 8 Sokoloff, 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.
  6. ↑ Type of Trithuria occidentalis Benth. [family HYDATELLACEAE]. (n.d.). JSTOR. Retrieved November 10, 2024, from https://plants.jstor.org/stable/10.5555/al.ap.specimen.bm000991248
  7. ↑ 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.
  8. ↑ Iles, W. J. D. (2013). The phylogeny and evolution of two ancient lineages of aquatic plants (Doctoral dissertation, University of British Columbia).
  9. ↑ Rudall, P. (n.d.). Tiny plants make a huge impact. Kew. Retrieved November 10, 2024, from https://www.kew.org/read-and-watch/tiny-plants-make-impact
  10. ↑ Eggli, U., & Newton, L. E. (2010). Etymological Dictionary of Succulent Plant Names. p. 170. Springer.
  11. ↑ A Grammatical Dictionary of Botanical Latin. (n.d.-d). Missouri Botanical Garden. Retrieved November 9, 2024, from http://www.mobot.org/mobot/latindict/keyDetail.aspx?keyWord=west
  12. ↑ Western Australian Herbarium & Department of Biodiversity, Conservation and Attractions. (n.d.). Trithuria occidentalis Benth. Florabase—the Western Australian Flora. Retrieved November 10, 2024, from https://florabase.dbca.wa.gov.au/browse/profile/32658
  13. ↑ Australian Government & Department of Climate Change, Energy, the Environment and Water. (n.d.). Trithuria occidentalis — Swan Hydatella. Species Profile and Threats Database. Retrieved November 10, 2024, from https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=42224
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