Trithuria

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Classis: Unassigned
Ordo: Nymphaeales

Familia: Hydatellaceae
Genus: Trithuria
Species: T. austinensis – T. australis – T. bibracteata – T. cookeana – T. cowieana – T. filamentosa – T. inconspicua – T. konkanensis – T. lanterna – T. polybracteata – T. submersa
Name

Trithuria Hook., Fl. Tasmaniae 2: 78. (1858)

Type species: Trithuria submersa (Hook.) Ewart

Synonyms

Homotypic
Juncella F.Muell. ex Hieron., Nat. Pflanzenfam. (Engler & Prantl) 2(4): 15. Oct 1887.
Heterotypic
Hydatella Diels, Bot. Jahrb. Syst. (Diels & Pritzel) 35: 93. 15 Apr 1904.

Distribution
Native distribution areas:

Continental: Africa
Regional: Tropical Africa

References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition
References
Primary references

Hooker, J.D. 1855–1857. The botany of the Antarctic voyage [...]. Part 3. Flora Tasmaniae. Vol. 1. (p. 1–80, 1855; p. 81–240 1856; p. 241–359, 1857). London: L. Reeve. BHL Reference page. : 2. 78

Links

Farr, E. R. & Zijlstra, G. eds. (1996-) Index Nominum Genericorum (Plantarum). 2009 Oct 01 [1].
Govaerts, R. et al. 2021. Trithuria in World Checklist of Selected Plant Families. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the internet. Accessed: 2021 Oct 14. Reference page.
International Plant Names Index. 2021. Trithuria. Published online. Accessed: Oct 14 2021.
Tropicos.org 2021. Trithuria. Missouri Botanical Garden. Published on the internet. Accessed: 2021 Oct 14.
Hassler, M. 2021. Trithuria. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2021. Species 2000 & ITIS Catalogue of Life. Published on the internet. Accessed: 2021 Oct 14. Reference page.

Vernacular names
فارسی: خزه‌وش‌ها
한국어: 트리투리아속
slovenčina: Vodniatka

Trithuria is a genus of small aquatic herb, which represent the only members of the family Hydatellaceae found in India, Australia, and New Zealand.[1][2] Most of the 12 formally characterised species of Trithuria are found in Australia, with the exception of T. inconspicua and T. konkanensis, which are found in New Zealand and India, respectively.[3][4] Until genetic testing proved otherwise, these plants were believed to be Monocots related to the grasses (Poaceae). They are unique in being the only plants besides Lacandonia schizmatica and L. braziliana in which the stamens are in the center of the flower while the pistels are circled in a ring around them. [5]

These diminutive, moss-like, aquatic plants are the closest living relatives of the two closely related families Nymphaeaceae (water-lilies) and Cabombaceae.[6] Together, these three families compose the order Nymphaeales in the APG III system of flowering plant classification. Trithuria (Hydatellaceae) diverged from the rest of Nymphaeales soon after Nymphaeales diverged from its sister taxon, which comprises all of the flowering plants except the two orders Nymphaeales and Amborellales.
Taxonomy

The genus Hydatella was recently subsumed into Trithuria based on the following morphological synapomorphies:[3]

lack of a vascular cambium,
lack of pericyclic sclerenchyma,
anomocytic stomata,
truncate anther connective,
boat-shaped pollen,
inner integument with two cell layers,
palisade exotesta,
seed operculum formed by cell enlargement in the inner integument,
perisperm and
hypogeal germination.[7]

Species and distribution
Phylogeny of Trithuria[8][9]
 

	sect. Altofinia   T. cookeana     T. cowieana     sect. Hamannia   T. polybracteata       T. konkanensis     T. lanterna           sect. Trithuria   T. occidentalis       T. bibracteata     T. submersa       sect. Hydatella   T. austinensis       T. australis       T. filamentosa     T. inconspicua

 

Trithuria austinensis D.D.Sokoloff - Western Australia
Trithuria australis (Diels) D.D.Sokoloff - Western Australia
Trithuria bibracteata Stapf ex D.A.Cooke - Western Australia
Trithuria cookeana D.D.Sokoloff, Remizowa, T.D.Macfarl. & Rudall - Northern Territory of Australia
Trithuria cowieana D.D.Sokoloff - Northern Territory
Trithuria filamentosa Rodway - Tasmania
Trithuria inconspicua Cheeseman - North Island of New Zealand
Trithuria konkanensis S.R.Yadav & Janarth. - Maharashtra
Trithuria lanterna D.A.Cooke - Northern Territory, Western Australia, Queensland
Trithuria occidentalis Benth. - Western Australia
Trithuria polybracteata D.A.Cooke ex D.D.Sokoloff, Remizowa, T.D.Macfarl. & Rudall - Western Australia
Trithuria submersa Hook.f. - Western Australia, South Australia, Victoria, New South Wales, Tasmania

References

Kew World Checklist of Selected Plant Families
Marques, Isabel; Montgomery, Sean A.; Barker, Michael S.; Macfarlane, Terry D.; Conran, John G.; Catalán, Pilar; Rieseberg, Loren H.; Rudall, Paula J.; Graham, Sean W. (2016-04-01). "Transcriptome-derived evidence supports recent polyploidization and a major phylogeographic division in Trithuria submersa (Hydatellaceae, Nymphaeales)". New Phytologist. 210 (1): 310–323. doi:10.1111/nph.13755. ISSN 1469-8137. PMID 26612464.
Dmitry D. Sokoloff, Margarita V. Remizowa, Terry D. Macfarlane, and Paula J. Rudall. 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.
Yadav SR, Janarthanam MK. 1995 Trithuria konkanensis (Hydatellaceae), eine neue Art aus Indien. Aqua Planta 20. (3): 91-97 (1995).
Rudall, Paula J. (February 4, 2016). "Inside-out flowers of Lacandonia brasiliana (Triuridaceae) provide new insights into fundamental aspects of floral patterning". PeerJ. 4: e1653. doi:10.7717/peerj.1653. PMC 4748704. PMID 26870611.
Else Marie Friis & Peter Crane (15 March 2007), "Botany: New home for tiny aquatics", Nature, 446 (7133): 269–270, Bibcode:2007Natur.446..269F, doi:10.1038/446269a, PMID 17361167
Jeffery M. Saarela1; et al. (15 March 2007), "Hydatellaceae identified as a new branch near the base of the angiosperm phylogenetic tree", Nature, 446 (7133): 312–315, Bibcode:2007Natur.446..312S, doi:10.1038/nature05612, PMID 17361182, S2CID 4415881
Sokoloff, Dmitry D.; Remizowa, Margarita V.; Beer, Anton S.; Yadav, Shrirang R.; Macfarlane, Terry D.; Ramsay, Margaret M.; Rudall, Paula J. (May 2013). "Impact of spatial constraints during seed germination on the evolution of angiosperm cotyledons: A case study from tropical Hydatellaceae (Nymphaeales)". American Journal of Botany. 100 (5): 824–843. doi:10.3732/ajb.1200620. PMID 23613353.
Iles, Will; Rudall, Paula J.; Sokoloff, D. D.; Graham, Sean W (March 2012). "Molecular phylogenetics of Hydatellaceae (Nymphaeales): Sexual-system homoplasy and a new sectional classification". American Journal of Botany. 99 (4): 663–676. doi:10.3732/ajb.1100524. PMID 22473977.