Dipentodon

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Dipentodon
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Huerteales
Family: Dipentodontaceae
Genus: Dipentodon
Dunn
Species:
D. sinicus
Binomial name
Dipentodon sinicus
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. [2] It has been little studied and until recently its affinities remained obscure.

Contents

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 [2] 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. [2] The hypanthium is very short [3] or else the ovary is superior. [2] 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. [4] At that time, Dunn wrote:

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, [5] but this placement was not generally followed. Instead, most authors put Dipentodon in the ill-defined and heterogeneous family Flacourtiaceae. [6] [7] [8] In the twenty-first century, Flacourtiaceae is recognized by only a few taxonomists, [9] and then only in a much narrower sense than it had been. [2] [10] Dipentodon is unrelated to Flacourtiaceae sensu stricto, a segregate of Salicaceae. [11] [12] Molecular phylogenetic studies have led to the widespread acceptance of the family Dipentodontaceae and its placement in the order Huerteales. [3] Some authors have defined the family as consisting only of Dipentodon. [13] Others, following the recommendation of a 2006 study, [14] have included Perrottetia. [2] [15] 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.

Related Research Articles

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.

Urticales is an order of flowering plants. Before molecular phylogenetics became an important part of plant taxonomy, Urticales was recognized in many, perhaps even most, systems of plant classification, with some variations in circumscription. Among these is the Cronquist system (1981), which placed the order in the subclass Hamamelidae [sic], as comprising:

Salicaceae Family of plants

The Salicaceae is the willow family of flowering plants. The traditional family included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly expanded the circumscription of the family to contain 56 genera and about 1220 species, including the Scyphostegiaceae and many of the former Flacourtiaceae.

Achariaceae Family of flowering plants

Achariaceae is a family of flowering plants consisting of 32-33 genera with about 155 species of tropical herbs, shrubs, and trees. The APG IV system has greatly expanded the scope of the family by including many genera previously classified in Flacourtiaceae. Molecular data strongly support the inclusion of this family in the order Malpighiales.

Samydaceae

Samydaceae is a family of tropical and subtropical woody plants, its best known genus being Casearia. It has always been of uncertain placement, in the past usually being submerged in the family Flacourtiaceae.

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.

Peridiscaceae Family of flowering plants in the order Saxifragales

Peridiscaceae is a family of flowering plants in the order Saxifragales. Four genera comprise this family: Medusandra, Soyauxia, Peridiscus, and Whittonia., with a total of 12 known species. It has a disjunct distribution, with Peridiscus occurring in Venezuela and northern Brazil, Whittonia in Guyana, Medusandra in Cameroon, and Soyauxia in tropical West Africa. Whittonia is possibly extinct, being known from only one specimen collected below Kaieteur Falls in Guyana. In 2006, archeologists attempted to rediscover it, however, it proved unsuccessful.

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.

Dipentodontaceae Family of flowering plants

Dipentodontaceae is a family of flowering plants containing two genera.

  1. DipentodonDunn - southern China, Assam, Myanmar
  2. PerrottetiaKunth in F.W.H.von Humboldt - southern China, Southeast Asia, Papuasia, Queensland, Hawaii, Latin America.
<i>Gerrardina</i> Genus of flowering plants

Gerrardina is a genus of two species of trees, shrubs, and scrambling shrubs found in southeastern Africa. Until recently, the genus was placed in the polyphyletic family Flacourtiaceae, but it was abnormal there due to its apical placentation, small embryos, and mucilaginous foliar epidermis. Analyses of DNA data indicated that the genus did not fit in any known plant family and not clearly in any then-recognized order, and a new family, Gerrardinaceae, was thus created for it. Later analyses of additional DNA data and data from wood anatomy indicated that the family should be placed in the order Huerteales.

Macrohasseltia is a monotypic genus of flowering plants in the family Salicaceae. It consists of one species of tree: Macrohasseltia macroterantha, which is native to Central America. Formerly placed in the heterogeneous family Flacourtiaceae, Macrohasseltia is now classified in Salicaceae, along with close relatives Bennettiodendron, Carrierea, Idesia, Itoa, Olmediella, Poliothyrsis, and even the willows (Salix) and cottonwoods (Populus) themselves.

<i>Olmediella</i> Genus of trees

Olmediella is a monotypic genus of flowering plants in the family Salicaceae. It consists of one species of trees: Olmediella betschleriana, which is native to Central America. Formerly placed in the heterogeneous family Flacourtiaceae, Olmediella is now classified in Salicaceae, along with close relatives Bennettiodendron, Carrierea, Idesia, Itoa, Macrohasseltia, Poliothyrsis, and even the willows (Salix) and cottonwoods (Populus) themselves.

Aphaerema was formerly a genus of flowering plants in the Flacourtiaceae, consisting of one species of small shrubs, Aphaerema spicata, which is native to Brazil and Argentina. Later studies indicated that Aphaerema should be classified in the willow family, Salicaceae, and combined with the genus Abatia. Unfortunately, because the name Abatia spicata was already used, the species was given the new name Abatia angeliana, in honor of Brazilian botanist João Angely. Aphaerema is one of the few groups of Salicaceae with opposite leaves.

Calantica is a genus of flowering plants in the family Salicaceae. It contains 10 species of shrubs and trees endemic to Madagascar, seven of which are threatened. Calantica is closely related to the pantropical and diverse genus Homalium, from which it differs in having a superior ovary, instead of a semi-inferior ovary. The genus is also similar to Bivinia in its superior ovary but has numerous stamens and long spiciform inflorescences.

Scyphostegia borneensis is a species of shrub or small tree endemic to Borneo. This unusual plant is the only species in the genus Scyphostegia. In many taxonomic classifications the genus was placed in its own family, the Scyphostegiaceae. Analyses of DNA data indicated that the species is related to a group of species of the now defunct Flacourtiaceae, a group which is now placed in a broadly circumscribed Salicaceae.

Ahernia is a genus of a single species of trees in the willow family Salicaceae found in Hainan province of China and Luzon island of the Philippines. Previously it was treated in the family Flacourtiaceae or Achariaceae. Ahernia is closely related to the American genera Hasseltia, Macrothumia, and Pleuranthodendron, but differs in its axillary racemes and more numerous (10–15) petals. Ahernia glandulosa is found in low elevation primary forests and is known in the Tagalog language as butun or sanglai. It grows 8–15 m (26–49 ft) tall.

Euceraea is a genus of three species of shrubs and small trees in the willow family Salicaceae native to the Guiana Shield of northeastern South America. Previously it was treated in the family Flacourtiaceae but was moved along with its close relatives to the Salicaceae based on analyses of DNA data. Euceraea is closely related to the genera Casearia and Neoptychocarpus, but differs in its inflorescences of composite spikes. One species, Euceraea rheophytica, is a rheophyte.

Irenodendron is a genus of three species of shrubs and trees in the willow family Salicaceae native to northern South America. These species were previously treated as a section of the genus Laetia in the family Flacourtiaceae, but the genus Laetia and its relatives were moved to the Salicaceae based on analyses of DNA data. Irenodendron was later hypothesized to be more closely related to the genera Ryania, Trichostephanus, and Piparea due to the presence of an apically divided style, and wood with dark heartwood and large rays; it differs from those genera in having cup-shaped bracts under the flowers and in lacking staminodes.

Zuelania guidonia is a species of shrub or tree native to the West Indies, Central America, and northern South America and is the only member of the genus Zuelania. Formerly classified in the Flacourtiaceae, phylogenetic analyses based on DNA data indicate that this species, along with its close relatives in Casearia, Samyda, Hecatostemon, and Laetia, are better placed in a broadly circumscribed Salicaceae. Zuelania differs from its close relatives in having a large, subsessile stigma.

Tetrathylacium is a genus of two species of shrubs and small trees in the family Salicaceae native to the southern Central America and northern South America. Previously it was treated in the family Flacourtiaceae but was moved along with its close relatives to the Salicaceae based on analyses of DNA data. Tetrathylacium is rather unique in the Samydaceae in having tightly arranged panicles of spikes, four sepals and stamens, and non-arillate seeds. The stems are often inhabited by ants, and T. macrophyllum is suspected to have locust pollination.

References

  1. ↑ World Conservation Monitoring Centre (1998). "Dipentodon sinicus". IUCN Red List of Threatened Species . 1998: e.T32338A9699283. doi: 10.2305/IUCN.UK.1998.RLTS.T32338A9699283.en . Retrieved 20 November 2021.
  2. 1 2 3 4 5 6 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.
  3. 1 2 Worberg Andreas; Alford Mac H.; Quandt Dietmar; Borsch Thomas (2009). "Huerteales sister to Brassicales plus Malvales, and newly circumscribed to include Dipentodon, Gerrardina, Huertea, Perrottetia, and Tapiscia". Taxon. 58 (2): 468–478. doi:10.1002/tax.582012.
  4. ↑ Dunn Stephen T (1911). "Dipentodon. A New Genus of Uncertain Systematic Position". Bulletin of Miscellaneous Information. 1911 (7): 310–313. doi:10.2307/4119481. JSTOR   4119481.
  5. ↑ Merrill Elmer D (1941). "Pages 69,73 In: The Upper Burma plants collected by Captain F. Kingdon Ward on the Vernay-Cutting Expedition, 1938-1939". Brittonia. 4 (1): 20–188. doi:10.2307/2804985. JSTOR   2804985. S2CID   42643687.
  6. ↑ YL Peng; ZD Chen; X Gong; Y Zhong; SH Shi Peng (2003). "Phylogenetic position of Dipentodon sinicus: evidence from DNA sequences of chloroplast rbcL, nuclear ribosomal 18S, and mitochondria matR genes" (PDF). Bull. Acad. Sin. 44: 217–222. ISSN   0006-8063.
  7. ↑ (in Chinese) 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.
  8. ↑ 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.
  9. ↑ Sue Zmarzty et alii. (in press). "Salicaceae" In: The Families and Genera of Vascular Plants. Springer-Verlag: Berlin;Heidelberg, Germany.
  10. ↑ Chase Mark W.; Zmarzty Sue; Lledó M. Dolores; Wurdack Kenneth J.; Swensen Susan M.; Fay Michael F. (2002). "When in doubt, put it in Flacourtiaceae: a molecular phylogenetic analysis based on plastid rbcL DNA sequences". Kew Bulletin. 57 (1): 141–181. doi:10.2307/4110825. JSTOR   4110825.
  11. ↑ Hengchang Wang; Michael J. Moore; Pamela S. Soltis; Charles D. Bell; Samuel F. Brockington; Roolse Alexandre; Charles C. Davis; Maribeth Latvis; Steven R. Manchester; Douglas E. Soltis (10 Mar 2009). "Rosid radiation and the rapid rise of angiosperm-dominated forests". Proceedings of the National Academy of Sciences. 106 (10): 3853–3858. Bibcode:2009PNAS..106.3853W. doi: 10.1073/pnas.0813376106 . PMC   2644257 . PMID   19223592.
  12. ↑ Zhu, Xy; Chase, Mw; Qiu, Yl; Kong, Hz; Dilcher, Dl; Li, Jh; Chen, Zd (November 2007). "Mitochondrial matR sequences help to resolve deep phylogenetic relationships in rosids". BMC Evolutionary Biology. 7: 217. doi:10.1186/1471-2148-7-217. PMC   2222252 . PMID   17996110.
  13. ↑ 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.
  14. ↑ Li-Bing Zhang; Simmons Mark P (2006). "Phylogeny and Delimitation of the Celastrales Inferred from Nuclear and Plastid Genes". Systematic Botany. 31 (1): 122–137. doi:10.1600/036364406775971778. S2CID   86095495.
  15. ↑ Peter F. Stevens (2001 onwards). "Huerteales". In: Angiosperm Phylogeny Website. In: Missouri Botanical Garden Website. (see External links below)
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