''Trithuria inconspicua'' is a small
aquatic herb
In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...
of the family
Hydatellaceae that is only found in
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
.
[Kew World Checklist of Selected Plant Families]
/ref>[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.]
Description
''Trithuria inconspicua'' is a small (~4 cm) fresh water lily
''Lilium'' () is a genus of Herbaceous plant, herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in mu ...
endemic to New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
. 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.[New Zealand Plant Conservation Network](_blank)
/ref> As the plant is Monoicous
Monoicy () is a sexual system in haploid plants (mainly bryophytes) where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both.Crandall-Stotler, B.J. ...
individual male and female flowers are found on the same plant, however, in nature plants containing flowers of both sexes are rare.[Pledge, David H. 1974. "Some Observations on Hydatella Inconspicua (Cheesem.) Cheesem. (Centrolepidaceae)." New Zealand Journal of Botany 12 (4): 559–61.] 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.
The first flowering plant?
Based on molecular data from a single plastid
The plastid (Greek: πλαστός; plastós: formed, molded – plural plastids) is a membrane-bound organelle found in the Cell (biology), cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracellular endosy ...
gene (rbcL)''T. inconspicua'' was originally believed to a monocot
Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of ...
.[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.] 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).[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.] This new placement of ''T. inconspicua'' means only a single lineage of flowering plant is thought to be older, that being the woody New Caledonia
)
, anthem = ""
, image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg
, map_alt = Location of New Caledonia
, map_caption = Location of New Caledonia
, mapsize = 290px
, subdivision_type = Sovereign st ...
n shrub ''Amborella trichopoda
''Amborella'' is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellale ...
''.[ Friis, Else Marie, and Peter Crane. 2007. "Botany: New Home for Tiny Aquatics." Nature 446 (7133): 269–70.]
The predominant view that ''Amborella
''Amborella'' is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellale ...
'' represents the oldest flowering plant was recently challenged in a study by Goremykini ''et al'' (2013),[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 Biology'' 61 (1) 50–61.] 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).[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.] 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
''Amborella'' is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellale ...
''. These competing theories have been given the light hearted monikers "wet and wild" and "dark and disturbed".[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.][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.]
Conservation status
''Trithuria inconspicua'' is seriously threatenedUtricularia gibba
''Utricularia gibba'', commonly known as the humped or floating bladderwort, is a small, mat-forming species of carnivorous aquatic bladderwort. It is found on all continents except Antarctica.
''U. gibba'' has an exceptionally small genome for ...
'') as well as othe
fresh water weeds
References
{{Taxonbar, from=Q24997654
Nymphaeales
Aquatic plants
Flora of New Zealand
Taxa named by Thomas Frederic Cheeseman
Dioecious plants