Systematics and Classification of Acanthaceae
Since my Ph.D. thesis primarily on Acanthaceae pollen I have continued the research focussing on floral development in relation to aestivation patterns, sequencing of ndhF and production of a new classification. Collaboration with Kaj Vollesen (Kew) and Richard Olmstead (Washington).
Systematics of Strobilanthes (Acanthaceae)
A central aim of the research is to write a taxonomic account of Strobilanthes. Recent emphasis has been on taxa from Sri Lanka and South India, Indonesia and the Philippines. The research is using both morphological and molecular data including detailed pollen and seed anatomy.
Molecular data include DNA sequence data from ndhF, trnL-F and ITS.The research has been conducted within the conceptual and theoretical framework of particular problems associated large genera. Thus we have been addressing issues in relation to a) character/taxon ratios in relation to measures of support and resolution (b) morphological data and phylogenetic accuracy c) morphological and molecular data and their respective roles in phylogeny reconstruction and classification. Collaboration with Richard Olmstead (Washington).
I continue with an active interest in systematic theory that has recently manifested itself in relation to character coding in the context of morphological cladistic analysis and three-item statement analysis.
Evolution & Development
A collaborative project has begun with Jane Langdale (Oxford) examining the role of rough sheath 2 and Knox genes in relation to the evolution of leaves.
I am working on Thomandersia Baill., a genus of six species of tropical African shrubs and small trees in the Lamiales. Traditionally placed in the Acanthaceae, the genus has been described as aberrant for every group with which it has been associated. I am carrying out a molecular phylogenetic analysis of the Lamiales as a whole, using the chloroplast genes rbc L and ndh F, to determine the true affinities of Thomandersia, which do not appear to lie in the Acanthaceae.
I am also undertaking morphological studies, including anatomical sectioning of flowers and fruits, to assess the true nature of the proposed homologies of Thomandersia with the Acanthaceae, and to identify similarities with other possible sister taxa. A taxonomic revision of the genus may also be necessary.
Current address: Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA 02138 USA
My work focused on the systematics of those species of Strobilanthes which are found outside of southern India and Sri Lanka. A survey of the diversity of pollen morphology was undertaken - a sample of which can be viewed here. ITS and trn L-F sequence data was used to investigate species relationships. In particular I looked at the relationship between the southern Indian and Sri Lankan species and those found outside this region.
A taxonomic revision of the Javanese species has been published (Kew Bulletin 58: 1 - 82 (2004), and a searchable on-line database of those species is available here.
I am now a postdoctoral fellow of the Arnold Arboretum, Harvard University, researching the molecular evolution of the phytochrome gene family in Orobanchacaeae. Further details are available here.
Current address: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB
I studied the systematics of Hemigraphis Nees in relation to Sericocalyx Bremek. and Strobilanthes Blume of the subtribe Strobilanthinae. The two aspects of my research were:
- species delimitation of Hemigraphis in the Philippines
- generic circumscription to test monophyly of the genus using ITS and trnL - trnF sequence data.
I am also interested in the floral anatomy of Hemigraphis. Standard sectioning techniques are being used to compare floral anatomical characteristics of Hemigraphis to other genera in the Strobilanthinae.
Current address: The Natural History Museum, Cromwell Road, London SW7 5BD
Two aspects of Strobilanthes systematics have been addressed: a taxonomic revision of the segregate genus Stenosiphonium and an investigation into species relationships among the southern Indian and Sri Lankan Strobilanthes using morphological and molecular data.
View Oxford Plant Systematics articles online: