In the past two decades, tremendous progress has been made in understanding relationships within angiosperms. The order- and family-level Tree of life of angiosperms has been reconstructed. However, due to relatively limited taxon sampling within families, those higher-level phylogenetic analyses of angiosperms did not clarify the circumscriptions of some heterogeneous families.
Capparaceae (Brassicales) as traditionally circumscribed is heterogeneous, and several genera have been segregated from it based on molecular and/or morphological data. Borthwickia, one Southeast Asian endemic genus of Capparaceae with controversial position and taxonomic rank, has not previously been evaluated in a molecular phylogenetic study. Dr. CHEN Zhiduan’s group from State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, CAS used four plastid DNA regions (matK, ndhF, rbcL, and trnL-trnF) and pollen data to determine its phylogenetic relationship within core Brassicales. Their results show that Borthwickia is not a member of Capparaceae. Instead Borthwickia is sister to the Forchhammeria-Resedaceae-Stixis-Tirania clade with moderate to strong support. However, Borthwickia differs markedly from its sister group in having opposite leaves, one indistinct stigma, more than four carpels and locules, a linear ovary with ridges, and pollen grains with perforate exine sculpturing. Thus, a new family, Borthwickiaceae, for the genus, was established. This paper was just published in Taxon (2012, 61(3): 601-611), which has been cited by AP-Web (http://www.mobot.org/MOBOT/research/APweb/).
Among angiosperms, there are so far only four families established by the Chinese authors: Torricelliaceae Hu (1934), Barclayaceae H. L. Li (1955), Acanthochlamydaceae P. C. Kao (1989), and Borthwickiaceae J. X. Su, Wei Wang, Li Bing Zhang & Z. D. Chen (2012). However, both Barclayaceae and Acanthochlamydaceae were not accepted by APG classification system. Therefore, the new established family by Zhiduan Chen’s group is the second family named by the Chinese and accepted by APG system.
This work indicates that future direction of plant phylogenetics will be to expand comprehensive comparisons beyond the level of orders and families, to that of genera and species.This work was financially supported by the National Natural Science Foundation of China, and CAS Visiting Professorship for Senior International Scientists.
To see the paper, please click:http://sourcedb.ib.cas.cn/cn/ibthesis/201207/P020120712407111904005.pdf
For more information, please contact Professor CHEN Zhiduan at: zhiduan@ibcas.ac.cn
Borthwickiaceae Plant and its systematic position
In the past two decades, tremendous progress has been made in understanding relationships within angiosperms. The order- and family-level Tree of life of angiosperms has been reconstructed. However, due to relatively limited taxon sampling within families, those higher-level phylogenetic analyses of angiosperms did not clarify the circumscriptions of some heterogeneous families.
Capparaceae (Brassicales) as traditionally circumscribed is heterogeneous, and several genera have been segregated from it based on molecular and/or morphological data. Borthwickia, one Southeast Asian endemic genus of Capparaceae with controversial position and taxonomic rank, has not previously been evaluated in a molecular phylogenetic study. Dr. CHEN Zhiduan’s group from State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, CAS used four plastid DNA regions (matK, ndhF, rbcL, and trnL-trnF) and pollen data to determine its phylogenetic relationship within core Brassicales. Their results show that Borthwickia is not a member of Capparaceae. Instead Borthwickia is sister to the Forchhammeria-Resedaceae-Stixis-Tirania clade with moderate to strong support. However, Borthwickia differs markedly from its sister group in having opposite leaves, one indistinct stigma, more than four carpels and locules, a linear ovary with ridges, and pollen grains with perforate exine sculpturing. Thus, a new family, Borthwickiaceae, for the genus, was established. This paper was just published in Taxon (2012, 61(3): 601-611), which has been cited by AP-Web (http://www.mobot.org/MOBOT/research/APweb/).
Among angiosperms, there are so far only four families established by the Chinese authors: Torricelliaceae Hu (1934), Barclayaceae H. L. Li (1955), Acanthochlamydaceae P. C. Kao (1989), and Borthwickiaceae J. X. Su, Wei Wang, Li Bing Zhang & Z. D. Chen (2012). However, both Barclayaceae and Acanthochlamydaceae were not accepted by APG classification system. Therefore, the new established family by Zhiduan Chen’s group is the second family named by the Chinese and accepted by APG system.
This work indicates that future direction of plant phylogenetics will be to expand comprehensive comparisons beyond the level of orders and families, to that of genera and species.This work was financially supported by the National Natural Science Foundation of China, and CAS Visiting Professorship for Senior International Scientists.
To see the paper, please click:http://sourcedb.ib.cas.cn/cn/ibthesis/201207/P020120712407111904005.pdf
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| Borthwickiaceae Plant and its systematic position |