Dipentodon
{{Short description|Genus of trees}}
{{Speciesbox
|image =
|status = LR/lc
|status_system = IUCN2.3
|genus = Dipentodon
|parent_authority = Dunn
|species = sinicus
|authority = Dunn
}}
Dipentodon is a genus of flowering plants in the family Dipentodontaceae. Its only species, Dipentodon sinicus, is a small, deciduous tree native to southern China, northern Myanmar, and northern India.Jinshuang Ma and Bruce Bartholomew. 2008. "Dipentodontaceae" pages 494-495. In: Zhengyi Wu, Peter H. Raven, and Deyuan Hong (editors). Flora of China volume 11. Science Press: Beijing, China; Missouri Botanical Garden Press: St. Louis, Missouri, USA. It has been little studied and until recently its affinities remained obscure.
Description
Dipentodon sinicus is a small, deciduous tree. The leaves are stipulate, alternate, and simple, with serrate margins. The inflorescence is variable in form, usually an abbreviated, umbelliform cyme containing 25 to 30 small flowers. The flowers are actinomorphic and yellowish green. The sepals and petals are only weakly differentiated, usually 5, rarely to 7 in number, free, or united only at the base. The hypanthium is very short {{cite journal |author1=Worberg Andreas |author2=Alford Mac H. |author3=Quandt Dietmar |author4=Borsch Thomas | year = 2009 | title = Huerteales sister to Brassicales plus Malvales, and newly circumscribed to include Dipentodon, Gerrardina, Huertea, Perrottetia, and Tapiscia | journal = Taxon | volume = 58 | issue = 2| pages = 468–478 |doi=10.1002/tax.582012 }} or else the ovary is superior. The nectary disk is intrastaminal. The stamens are opposite the sepals. The ovary consists of three united carpels with two ovules per carpel. The ovary is 1-loculate, but partly 3-loculate at its base. The fruit is a 1-seeded drupaceous capsule.
History
Dipentodon was named and first described in 1911 by Stephen Troyte Dunn in what is now called the Kew Bulletin.{{cite journal | doi = 10.2307/4119481 | author = Dunn Stephen T | year = 1911 | title = Dipentodon. A New Genus of Uncertain Systematic Position | url =https://zenodo.org/record/1449880 | journal = Bulletin of Miscellaneous Information | volume = 1911 | issue = 7| pages = 310–313 | jstor = 4119481 }} At that time, Dunn wrote:
{{cquote|The name Dipentodon, proposed for it, refers to the most remarkable character possessed by the flowers in the exact similarity of the calyx teeth and petals (if I rightly call them so) and their insertion so nearly in one whorl that the appearance is given of a ten-toothed perianth.}}
Dipentodon was placed in its own family by Elmer Drew Merrill in 1941,{{cite journal | author = Merrill Elmer D | year = 1941 | title = Pages 69,73 In: The Upper Burma plants collected by Captain F. Kingdon Ward on the Vernay-Cutting Expedition, 1938-1939 | url = https://digitalcommons.butler.edu/cgi/viewcontent.cgi?article=1379&context=jhcs| journal = Brittonia | volume = 4 | issue = 1| pages = 20–188 | doi = 10.2307/2804985| jstor = 2804985 | s2cid = 42643687 | url-access = subscription }} but this placement was not generally followed. Instead, most authors put Dipentodon in the ill-defined and heterogeneous family Flacourtiaceae.{{cite journal | url = http://ejournal.sinica.edu.tw/bbas/content/2003/3/bot443-06.pdf |author1=YL Peng |author2=ZD Chen |author3=X Gong |author4=Y Zhong |author5=SH Shi Peng | journal = Bull. Acad. Sin. | year = 2003 | volume = 44 | pages = 217–222 | title = Phylogenetic position of Dipentodon sinicus: evidence from DNA sequences of chloroplast rbcL, nuclear ribosomal 18S, and mitochondria matR genes | issn = 0006-8063 }}{{in lang|zh}} Wu, Lu, A.-M., Tang, Y.-C., Chen, Z.-D., & Li, D.-Z. (2002). Synopsis of a new "polyphyletic-polychronic-polytopic" system of the angiosperms. Acta Phytotax. Sinica, 40: 298-322.Wu, Lu, A.-M., Tang, Y.-C., Chen, Z.-D., & Li, D.-Z. (2003). The Families and Genera of Angiosperms in China: A Comprehensive Analysis. Science Press, Beijing. In the twenty-first century, Flacourtiaceae is recognized by only a few taxonomists,Sue Zmarzty et alii. (in press). "Salicaceae" In: The Families and Genera of Vascular Plants. Springer-Verlag: Berlin;Heidelberg, Germany. and then only in a much narrower sense than it had been.{{cite journal | doi = 10.2307/4110825 |author1=Chase Mark W. |author2=Zmarzty Sue |author3=Lledó M. Dolores |author4=Wurdack Kenneth J. |author5=Swensen Susan M. |author6=Fay Michael F. | year = 2002 | title = When in doubt, put it in Flacourtiaceae: a molecular phylogenetic analysis based on plastid rbcL DNA sequences | journal = Kew Bulletin | volume = 57 | issue = 1| pages = 141–181 |jstor=4110825 |bibcode=2002KewBu..57..141C }} Dipentodon is unrelated to Flacourtiaceae sensu stricto, a segregate of Salicaceae.{{Cite journal |author1=Hengchang Wang |author2=Michael J. Moore |author3=Pamela S. Soltis |author4=Charles D. Bell |author5=Samuel F. Brockington |author6=Roolse Alexandre |author7=Charles C. Davis |author8=Maribeth Latvis |author9=Steven R. Manchester |author10=Douglas E. Soltis | title = Rosid radiation and the rapid rise of angiosperm-dominated forests | journal = Proceedings of the National Academy of Sciences | volume = 106 | issue = 10 | pages = 3853–3858 | date = 10 Mar 2009 | doi = 10.1073/pnas.0813376106 | pmid = 19223592 | pmc = 2644257 |bibcode=2009PNAS..106.3853W |doi-access=free }}{{cite journal | doi = 10.1186/1471-2148-7-217 | pmc = 2222252 | url = |date=November 2007 |author1=Zhu, Xy |author2=Chase, Mw |author3=Qiu, Yl |author4=Kong, Hz |author5=Dilcher, Dl |author6=Li, Jh |author7=Chen, Zd | title = Mitochondrial matR sequences help to resolve deep phylogenetic relationships in rosids | volume = 7 | pages = 217| pmid = 17996110 | journal = BMC Evolutionary Biology | issue = 1 | doi-access = free | bibcode = 2007BMCEE...7..217Z }} Molecular phylogenetic studies have led to the widespread acceptance of the family Dipentodontaceae and its placement in the order Huerteales. Some authors have defined the family as consisting only of Dipentodon.Vernon H. Heywood, Richard K. Brummitt, Ole Seberg, and Alastair Culham. Flowering Plant Families of the World. Firefly Books: Ontario, Canada. (2007). {{ISBN|978-1-55407-206-4}}. Others, following the recommendation of a 2006 study,{{cite journal | doi = 10.1600/036364406775971778 |author1=Li-Bing Zhang |author2=Simmons Mark P | year = 2006 | title = Phylogeny and Delimitation of the Celastrales Inferred from Nuclear and Plastid Genes | journal = Systematic Botany | volume = 31 | issue = 1| pages = 122–137 |s2cid=86095495 }} have included Perrottetia.Peter F. Stevens (2001 onwards). "Huerteales". In: Angiosperm Phylogeny Website. In: Missouri Botanical Garden Website. (see External links below) When the APG II classification was published in 2003, the taxonomic position of Dipentodon was still unknown and it was placed incertae sedis in the angiosperms. It was listed in the appendix under TAXA OF UNCERTAIN POSITION.
References
{{Reflist}}
External links
- [http://www.mobot.org/MOBOT/Research/APweb/orders/huertealesweb.htm#Huerteales Huerteales] At: [http://www.mobot.org/MOBOT/Research/APweb/welcome.html Angiosperm Phylogeny Website] At: [http://www.mobot.org Missouri Botanical Garden Website]
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Category:Flora of Assam (region)