Trithuria inconspicua

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Trithuria inconspicua
Trithuria inconspicua iNat2.jpg
Trithuria inconspicua growing in fine silica sand
Status NZTCS NC.svg
Nationally Critical (NZ TCS) [1]
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Order: Nymphaeales
Family: Hydatellaceae
Genus: Trithuria
T. inconspicua
Binomial name
Trithuria inconspicua
Distribution of Trithuria inconspicua
Synonyms [2]

Hydatella inconspicua (Cheeseman) Cheeseman

Trithuria inconspicua is a small aquatic herb of the family Hydatellaceae that is only found in New Zealand. [3] [4]



T. inconspicua partially buried under sediment. Photo by Jeremy Rolfe Trithuria inconspicua lake.jpg
T. inconspicua partially buried under sediment. Photo by Jeremy Rolfe

Trithuria inconspicua is a small (~4 cm) fresh water lily endemic to New Zealand. This lily grows in 5–7 meters of water and is restricted to the fresh water lakes of Northland and Fiordland regions of the North and South Island, respectively. Consisting of multiple 20–40 mm small tussocks and fibrous roots the plant is often partially buried under sediment or algae with only the leaf tips exposed. [1] As the plant is Monoicous individual male and female flowers are found on the same plant, however, in nature plants containing flowers of both sexes are rare. [5] The male flowers consist of bright red 10 mm long filaments, whilst the female flowers are yellow-brown and contain 5-10 styles bunched at the apex. [1]

There are two subspecies, Trithuria inconspicua subsp. inconspicua is found in dune lakes of Northland in the far north of the North Island, and T. inconspicua subsp. brevistyla is found in glacial lakes of the southern South Island (Smissen R.D., Ford K.A. Champion, P.D. and Heenan, P.B., Australian Systematic Botany 32(1): 1-11 (2019).

The first flowering plant?

Based on molecular data from a single plastid gene (rbcL)T. inconspicua was originally believed to a monocot. [6] However, a more recent study using multiple genetic loci, supported by a subsequent re-evaluation of morphological characteristics, now places T. inconspicua as a sister group with the water lilies (Nymphaeales). [7] This new placement of T. inconspicua means only a single lineage of flowering plant is thought to be older, that being the woody New Caledonian shrub Amborella trichopoda . [8]

The predominant view that Amborella represents the oldest flowering plant was recently challenged in a study by Goremykini et al (2013), [9] who showed that when highly variable sites were removed from the dataset, T. inconspicua was consistently identified as the oldest angiosperm lineage. This proposal has attracted criticism from Drew et al (2014), who argued that the basal placement of T. inconspicua is an artifact of the variable site filtering method used by Goremykini et al (2013). [10] One of the main reasons why people are interested in this question is that placing T. inconspicua at the base of the angiosperm lineage would suggest the first angiosperms were soft bodied aquatic plants, rather than a woody terrestrial plants like Amborella . These competing theories have been given the light hearted monikers "wet and wild" and "dark and disturbed". [10] [11] [12]

Conservation status

Trithuria inconspicua is seriously threatened [1] due to the competition by the introduced bladder wort ( Utricularia gibba ) as well as other fresh water weeds.

Related Research Articles

Flowering plant Clade of seed plants that produce flowers

Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae, commonly called angiosperms. The term "angiosperm" is derived from the Greek words angeion and sperma ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta.

Malpighiales Eudicot order of flowering plants

The Malpighiales comprise one of the largest orders of flowering plants, containing about 36 families and more than 16,000 species, about 7.8% of the eudicots. The order is very diverse, containing plants as different as the willow, violet, poinsettia, manchineel, rafflesia and coca plant, and are hard to recognize except with molecular phylogenetic evidence. It is not part of any of the classification systems based only on plant morphology. Molecular clock calculations estimate the origin of stem group Malpighiales at around 100 million years ago (Mya) and the origin of crown group Malpighiales at about 90 Mya.

Poales Order of monocotyledonous flowering plants

The Poales are a large order of flowering plants in the monocotyledons, and includes families of plants such as the grasses, bromeliads, and sedges. Sixteen plant families are currently recognized by botanists to be part of Poales.

Saxifragales Order of Eudicot flowering plants in the Superrosid clade

The Saxifragales (saxifrages) are an order of flowering plants (Angiosperms). They are an extremely diverse group of plants which include trees, shrubs, perennial herbs, succulent and aquatic plants. The degree of diversity in terms of vegetative and floral features makes it difficult to define common features that unify the order.

Nymphaeales Order of flowering plants

The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae. It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants. At least 10 morphological characters unite the Nymphaeales. Molecular synapomorphies are also known.

Monocotyledon Important clade of flowering plants

Monocotyledons, commonly referred to as monocots, are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided; the rest of the flowering plants have two cotyledons and are classified as dicotyledons, or dicots.

Nymphaeaceae Family of plants

Nymphaeaceae is a family of flowering plants, commonly called water lilies. They live as rhizomatous aquatic herbs in temperate and tropical climates around the world. The family contains five genera with about 70 known species. Water lilies are rooted in soil in bodies of water, with leaves and flowers floating on or emergent from the surface. Leaves are round, with a radial notch in Nymphaea and Nuphar, but fully circular in Victoria and Euryale.

<i>Amborella</i> Species of shrub

Amborella is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia. The genus is the only member of the family Amborellaceae and the order Amborellales and contains a single species, Amborella trichopoda. Amborella is of great interest to plant systematists because molecular phylogenetic analyses consistently place it as the sister group to all other flowering plants.

Embryophyte Subclade of green plants, also known as land plants

The Embryophyta, or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophyta is a clade within the Phragmoplastophyta, a larger clade that also includes several groups of green algae including the Charophyceae and Coleochaetales. Within this larger clade the embryophytes are sister to the Zygnematophyceae/Mesotaeniaceae and consist of the bryophytes plus the polysporangiophytes. Living embryophytes therefore include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms and flowering plants.The land plants have diplobiontic life cycles and is shown that the Charophycean green algae gave rise to land plants.

Limnanthaceae Family of flowering plants

The Limnanthaceae are a small family of annual herbs occurring throughout temperate North America. There are eight species and nineteen taxa currently recognized. Members of this family are prominent in vernal pool communities of California. Some taxa have been domesticated for use as an oil seed crop. Some members are listed as threatened or endangered and have been the focus of disputes over development plans

Rosids Large clade of flowering plants

The rosids are members of a large clade of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms.

Cabombaceae Family of flowering plants

The Cabombaceae are a family of aquatic, herbaceous flowering plants. A common name for its species is water shield. The family is recognised as distinct in the Angiosperm Phylogeny Group IV system (2016). The family consists of two genera of aquatic plants, Brasenia and Cabomba, totalling six species.

Hydnoroideae A subfamily of flowering plants comprising parasitic taxa

Hydnoroideae is a subfamily of parasitic flowering plants in the order Piperales. Traditionally, and as recently as the APG III system it given family rank under the name Hydnoraceae. It is now submerged in the Aristolochiaceae. It contains two genera, Hydnora and Prosopanche:

Hydatellaceae Family of flowering plants

Hydatellaceae are a family of small, aquatic flowering plants. The family consists of tiny, relatively simple, plants occurring in Australasia and India. It was formerly considered to be related to the grasses and sedges, but has been reassigned to the order Nymphaeales as a result of DNA and morphological analyses showing that it represents one of the earliest groups to split off in flowering-plant phylogeny, rather than having a close relationship to monocots, which it bears a superficial resemblance to due to convergent evolution. The family includes only the genus Trithuria, which has at least 13 species, although species diversity in the family has probably been substantially underestimated.

Huerteales Order of flowering plants

Huerteales is the botanical name for an order of flowering plants. It is one of the 17 orders that make up the large eudicot group known as the rosids in the APG III system of plant classification. Within the rosids, it is one of the orders in Malvidae, a group formerly known as eurosids II and now known informally as the malvids. This is true whether Malvidae is circumscribed broadly to include eight orders as in APG III, or more narrowly to include only four orders. Huerteales consists of four small families, Petenaeaceae, Gerrardinaceae, Tapisciaceae, and Dipentodontaceae.

<i>Trithuria</i> Genus of aquatic plants

Trithuria is a genus of small aquatic herb, which represent the only members of the family Hydatellaceae found in India, Australia, and New Zealand. 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. 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.

<i>Nymphaea odorata</i> Species of aquatic plant

Nymphaea odorata, also known as the American white waterlily, fragrant water-lily, beaver root, fragrant white water lily, white water lily, sweet-scented white water lily, and sweet-scented water lily, is an aquatic plant belonging to the genus Nymphaea. It can commonly be found in shallow lakes, ponds, and permanent slow moving waters throughout North America where it ranges from Central America to northern Canada. It is also reported from Brazil and Guyana.

Basal angiosperms Descendants of most extant flowering plants

The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade which is made up of Amborella, Nymphaeales and Austrobaileyales.

Mesangiospermae One of two clades of flowering plants

Mesangiospermae is a clade of flowering plants (angiosperms), informally called "mesangiosperms". They are one of two main groups of angiosperms. It is a name created under the rules of the PhyloCode system of phylogenetic nomenclature. There are about 350,000 species of mesangiosperms. The mesangiosperms contain about 99.95% of the flowering plants, assuming that there are about 175 species not in this group and about 350,000 that are. While such a clade with a similar circumscription exists in the APG III system, it was not given a name.

<i>Hydrostachys</i> Genus of flowering plants

Hydrostachys is a genus of about 22 species of flowering plants native to Madagascar and southern and central Africa. It is the only genus in the family Hydrostachyaceae. All species of Hydrostachys are aquatic, growing on rocks in fast-moving water. They have tuberous roots, usually pinnately compound leaves, and highly reduced flowers on dense spikes.


  1. 1 2 3 4 New Zealand Plant Conservation Network
  2. "Trithuria inconspicua Cheeseman". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 18 May 2022.
  3. Kew World Checklist of Selected Plant Families
  4. 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". Taxon57(1):179-200.
  5. Pledge, David H. 1974. "Some Observations on Hydatella Inconspicua (Cheesem.) Cheesem. (Centrolepidaceae)." New Zealand Journal of Botany 12 (4): 559–61.
  6. Michelangeli, Fabian A., Jerrold I. Davis, and Dennis Wm Stevenson. 2003. "Phylogenetic Relationships among Poaceae and Related Families as Inferred from Morphology, Inversions in the Plastid Genome, and Sequence Data from the Mitochondrial and Plastid Genomes." American Journal of Botany 90 (1): 93–106.
  7. Saarela, Jeffery M., Hardeep S. Rai, James A. Doyle, Peter K. Endress, Sarah Mathews, Adam D. Marchant, Barbara G. Briggs, and Sean W. Graham. 2007. "Hydatellaceae Identified as a New Branch near the Base of the Angiosperm Phylogenetic Tree." Nature 446 (7133): 312–15.
  8. Friis, Else Marie, and Peter Crane. 2007. "Botany: New Home for Tiny Aquatics." Nature 446 (7133): 269–70.
  9. Goremykini, V.V.; Nikiforova, S.V.; Biggs, P.J.; Zhong, B. de Lange, P.; Martin, W.; Woetzel, S.; Atherton, R.A., McLenachan, T.; Lockhart, P.J. 2013: The evolutionary root of flowering plants. Systematic Biology61 (1) 50–61.
  10. 1 2 Drew, Bryan T., Brad R. Ruhfel, Stephen A. Smith, Michael J. Moore, Barbara G. Briggs, Matthew A. Gitzendanner, Pamela S. Soltis, and Douglas E. Soltis. 2014. "Another Look at the Root of the Angiosperms Reveals a Familiar Tale." Systematic Biology 63 (3): 368–82.
  11. Feild, Taylor S., Nan Crystal Arens, James A. Doyle, Todd E. Dawson, and Michael J. Donoghue. 2004. "Dark and Disturbed: A New Image of Early Angiosperm Ecology." Paleobiology 30 (1): 82–107.
  12. Coiffard, C., B. Gomez, and F. Thevenard. 2007. "Early Cretaceous Angiosperm Invasion of Western Europe and Major Environmental Changes." Annals of Botany 100 (3): 545–53.