''Tetracarpaea'' is the only genus in the flowering plant family Tetracarpaeaceae.Richard K. Brummitt. 2007. "Tetracarpaeaceae" pages 316-317. In: Vernon H. Heywood, Richard K. Brummitt, Ole Seberg, and Alastair Culham. ''Flowering Plant Families of the World''. Firefly Books: Ontario, Canada. .Klaus Kubitzki. 2007. "Tetracarpaeaceae" pages 456-457. In: Klaus Kubitski (editor). ''The Families and Genera of Vascular Plants'' volume IX. Springer-Verlag: Berlin;Heidelberg, Germany. Some taxonomists place it in the family Haloragaceae '' sensu lato'', expanding that family from its traditional circumscription to include '' Penthorum'' and ''Tetracarpaea'', and sometimes ''

Aphanopetalum ''Aphanopetalum'' is a genus of twining shrubs or vines in the family Aphanopetalaceae which are endemic to Australia. The genus is placed alone in family Aphanopetalaceae, which is in turn now placed in order Saxifragales. Until recently th ...

'' as well.Shuguang Jian,

Pamela S. Soltis Pamela Soltis (born November 13, 1957) is an American botanist. She is a distinguished professor at the University of Florida, curator at the Florida Museum of Natural History, principal investigator of the Laboratory of Molecular Systematics an ...

, Matthew A. Gitzendanner, Michael J. Moore, Ruiqi Li, Tory A. Hendry, Yin-Long Qiu, Amit Dhingra, Charles D. Bell, and Douglas E. Soltis. 2008. "Resolving an Ancient, Rapid Radiation in Saxifragales". ''Systematic Biology'' 57(1):38-57. (see ''External links'' below). ''Tetracarpaea'' has one species, ''Tetracarpaea tasmannica'', an evergreen, bushy

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

from subalpine areas of Tasmania. It is variable in height, from 1.5 to 10 dm. The leaves are shiny and small, with prominent veins, and the ends of the branches are crowded with small, white flowers. It is not known in cultivation, but has been grown from cuttings.John W. Wrigley and Murray Fagg. 2003. ''Australian Native Plants'' fifth edition. Reed New Holland, Australia. ''Tetracarpaea'' has an odd mix of characters, and during the nineteenth and twentieth centuries, its

affinities In post-classical history, an affinity was a collective name for the group ( retinue) of (usually) men whom a lord gathered around himself in his service; it has been described by one modern historian as "the servants, retainers, and other foll ...

remained obscure. It was variously

classified Classified may refer to: General *Classified information, material that a government body deems to be sensitive *Classified advertising or "classifieds" Music *Classified (rapper) (born 1977), Canadian rapper *The Classified, a 1980s American roc ...

by different authors, usually with considerable uncertainty.Matthew H. Hils, William C. Dickison, Terry W. Lucansky, and William Louis Stern. 1988. "Comparative anatomy and systematics of woody Saxifragaceae: Tetracarpaea". ''American Journal of Botany'' 75(11):1687-1700.

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analysis of

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

s has shown that ''Tetracarpaea'' is a member of the Haloragaceae alliance, an informal group composed of the families Aphanopetalaceae, Tetracarpaeaceae, Penthoraceae, and Haloragaceae. These are four of the fourteenAngiosperm Phylogeny Group. 2009. "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". ''Botanical Journal of the Linnean Society'' 161(2):105-121. (see ''External links'' below). or fifteen families in the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Saxifragales.

Description

The following description is based on information from several sources.Armen L. Takhtajan (Takhtadzhian). ''Flowering Plants'' second edition (2009), pages 304-305. Springer Science+Business Media. . . (see ''External links'' below) Frances Bodkin. 1986. ''Encyclopaedia Botanica: The Essential Reference Guide to Native and Exotic Plants in Australia''. Angus and Robertson, Publishers: New South Wales, Australia; London, England. ''Tetracarpaea tasmannica'' is a glabrous, evergreen, erect and bushy

. It is variable in height, usually from 1.5 to 6 dm, but sometimes attaining a height of 1 m and a width of 7 dm. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are elliptic to oblanceolate, about 25 mm long and 8 mm wide, on a petiole about 2 mm long. The veins are prominent and end near the margin. The

margins Margin may refer to: Physical or graphical edges *Margin (typography), the white space that surrounds the content of a page *Continental margin, the zone of the ocean floor that separates the thin oceanic crust from thick continental crust *Leaf ...

are serrate or crenate. On both surfaces, the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...

is covered by a thick

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

. The inflorescences are dense, erect, terminal

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s, up to 5 cm long. The flowers appear in

autumn Autumn, also known as fall in American English and Canadian English, is one of the four temperate seasons on Earth. Outside the tropics, autumn marks the transition from summer to winter, in September ( Northern Hemisphere) or March ( Sou ...

. They are bisexual, actinomorphic, and 5 to 10 mm wide. The 4 sepals persist to the maturity of the fruit. The 4

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s are white and spatulate in shape. The

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s are either 4 or 8 in number. If 4, they are opposite (along the same radii as) the sepals. The

anther The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s are basifixed. The

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

superior Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake ...

and consists of 4 carpels that are large compared to the rest of the flower. The carpels are usually separate, but occasionally 2 or 3 of them are fused at the base, or rarely, as far as halfway up. They are erect and stipitate with a suture along the ventral side. A placenta runs along each side of the suture and bears 1 to 3 rows of numerous, tiny ovules. The ovules have been described as having one integument or two. The ovary hardly enlarges after anthesis. The fruit consists of 4 follicles joined at the base. The seeds are numerous and about ½ mm long.

Relationships

Named by

William Jackson Hooker Sir William Jackson Hooker (6 July 178512 August 1865) was an English botanist and botanical illustrator, who became the first director of Kew when in 1841 it was recommended to be placed under state ownership as a botanic garden. At Kew he ...

in 1840, the name ''Tetracarpaea'' refers to the four conspicuous and separate carpels.William Jackson Hooker. 1840. ''Hooker's Icones Plantarum'' volume 3. page 56 and table 264. Longman, Orme, Brown, Green, and Longmans: London, England. (see ''External links'' below). At that time, he wrote: Hooker did not use the modern system of suffixes for taxonomic ranks. He placed ''Tetracarpaea'' in what would later be known as the family Cunoniaceae. From that time, until the end of the twentieth century, most authors put it in either Cunoniaceae, Escalloniaceae, or Saxifragaceae. It was believed that these three families were related, but today, they are placed in separate orders.Peter F. Stevens. 2001 onwards. Angiosperm Phylogeny Website At: Missouri Botanical Garden Website. (see ''External links'' below). It is now known that Cunoniaceae belongs in Oxalidales.Jason C. Bradford, Helen C. Fortune-Hopkins, and Richard W. Barnes. 2004. "Cunoniaceae". pages 91-111. In: Klaus Kubitski (editor). ''The Families and Genera of Vascular Plants'' volume VI. Springer-Verlag: Berlin;Heidelberg, Germany. Escalloniaceae is even more distant from ''Tetracarpaea'', being a member of an asterid group called the campanulids.Richard C. Winkworth, Johannes Lundberg, and Michael J. Donoghue. 2008. "Toward a resolution of Campanulid phylogeny, with special reference to the placement of Dipsacales". ''Taxon'' 57(1):53-65. In the

APG III system The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a fur ...

, it is assigned to the monofamilial order Escalloniales. Phylogenetic analysis of DNA has placed ''Tetracarpaea'' in the order Saxifragales, and in the "core Saxifragales", but no closer to Saxifragaceae. The family Saxifragaceae is now defined much more narrowly than it had been until 2001.Douglas E. Soltis, Robert K. Kuzoff, Mark E. Mort, Michael Zanis, Mark Fishbein, Larry Hufford, Jason Koontz, and Mary K. Arroyo. 2001. "Elucidating deep-level phylogenetic relationships in Saxifragaceae using sequences for six chloroplastic and nuclear DNA regions". ''Annals of the Missouri Botanical Garden'' 88(4):669-693.

History

After William Jackson Hooker named ''Tetracarpaea'' and placed it in Cunoniaceae, he was followed by George Bentham, who placed it in the same family.George Bentham. 1864. ''Flora Australiensis'' volume 2, page 445. Lovell Reeve & Co.: London, England. (see ''External links'' below). Bentham mistakenly attributed the name to "Hook.f." ( Joseph Dalton Hooker), an error that is still repeated today. In 1865, George Bentham and Joseph Hooker moved ''Tetracarpaea'' from Cunoniaceae to Escalloniaceae.George Bentham and Joseph Hooker. 1865. ''Genera Plantarum'' volume 1, part 2, pages 648-649. Lovell Reeve & Co.; Williams & Norgate: London, England. (see ''External links'' below). Adolf Engler put ''Tetracarpaea'' in Saxifragaceae, but

defined A definition is a statement of the meaning of a term (a word, phrase, or other set of symbols). Definitions can be classified into two large categories: intensional definitions (which try to give the sense of a term), and extensional defini ...

the latter so widely that it included what is now Escalloniaceae as a subfamily. Engler first placed ''Tetracarpaea'' in subfamily Escallonioideae, then later moved it to its own subfamily.H.G. Adolf Engler. 1930. "Tetracarpaea" page 183. In: H.G. Adolf Engler and Karl A.E. Prantl (editors). 1930. ''Die Natürlichen Pflanzenfamilien'' volume 18a. Verlag von Wilhelm Engelmann: Leipzig, Germany. In 1943, Takenoshin Nakai put ''Tetracarpaea'' in a family to itself and was the first to use the term "Tetracarpaeaceae".Takenoshin Nakai. 1943. ''Chosakuronbun Mokuroku'': 244. 20 Jul 1943.James L. Reveal. 2008 onward. "A Checklist of Family and Suprafamilial Names for Extant Vascular Plants." At: Home page of James L. Reveal and C. Rose Broome. (see ''External links'' below). John Hutchinson did not follow suit, but placed it in Escalloniaceae.John Hutchinson ''The Families of Flowering Plants'' 3rd edition. 1973. Oxford University Press. Arthur Cronquist put ''Tetracarpaea'' in Grossulariaceae.Arthur John Cronquist. 1981. "Grossulariaceae" pages 558-561. In: ''An Integrated System of Classification of Flowering Plants''. Columbia University Press: New York, NY, USA. This family is now understood to contain only the genus Ribes and is sister to Saxifragaceae.

Armen Takhtajan Armen Leonovich Takhtajan or Takhtajian ( hy, Արմեն Լևոնի Թախտաջյան; russian: Армен Леонович Тахтаджян; surname also transliterated Takhtadjan, Takhtadzhi︠a︡n or Takhtadzhian, pronounced takh-tuh-JA ...

has at different times put ''Tetracarpaea'' in Escalloniaceae and in Tetracarpaeaceae. Most recently, in 2009, he put it in Tetracarpaeaceae. In 1988, Matthew H. Hils, et alii, did a detailed study of the anatomy of the wood and leaves of ''Tetracarpaea''. They concluded that ''Tetracarpaea'' was much closer to Saxifragaceae than to Cunoniaceae or Escalloniaceae. The first

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies of the order Saxifragales were inconclusive because their results had only weak statistical support. In 2008, by comparing

s of the entire invert repeat region of the

chloroplast A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in ...

genome, Shuguang Jian et alii were able to determine the position of ''Tetracarpaea'' within Saxifragales. These results had strong bootstrap support.

Description

Relationships

History

References

External links