Myrtaceae
Recent Achievements
Collections (2001-2005)
The herbarium collections are maintained in a systematically up to date order with newly published genera and revisions implemented regularly. New material is incorporated into the herbarium within three months of its arrival in the section and incorporation backlogs tackled since 2001 have been significantly reduced. Normally, outgoing loans are processed within six weeks of receipt of request while returning loans are incorporated within eight weeks of arrival in section.
Available figures for 2004 and 2005 indicate that an average of 3,700 specimens are mounted and curated into the Myrtaceae collection per year. An average 300 identifications per year are provided to external institutions and individuals while an average of 150 specimens per year are sent on loan. The section receives visitors amounting to an average of 90 visitor days per year.
Approximately 200 targeted collections including material for DNA analysis have been made by Kew staff from the Brazilian states of São Paulo, Minas Gerais, Paraná and Rio de Janeiro, and from French Guiana. As a result, over c.200 new Myrtaceae samples have been added to the Kew DNA bank.
Baseline Plant Diversity Research (2001-2005)
An international Myrtaceae workshop was hosted at Kew in 2005 to consolidate existing inter-institutional collaboration in Neotropical Myrtaceae systematics this provided a networking opportunity for an international team of Myrtaceae experts to review the World Checklist of the Myrtaceae compiled by Rafäel Govaerts. A work providing reliable taxonomic data for c. 5,600 species, which will be of critical use to the wider Myrtaceae community and which contributes to Kew’s advance towards Target 1 of the Global Strategy for Plant Conservation and which is now available online.
Specimen databases have been developed for subtribe Myrciinae (c. 6,000 records to date) and for the large genus Syzygium s.l. (c. 4,100 records). The Myrciinae database is fully georeferenced with all types digitised and has been merged with data from the New York Botanical Garden. The total number of Myrtaceae records in Kew species databases is now c.12,000. 945 Eucalyptus and Angophora species have been imaged and databased as part of the GBIF funded contribution by Kew to the Australian Virtual Herbarium.
The Myrtaceae account of Flora of Tropical East Africa was published by Bernard Verdcourt in 2001. The new genus Algrizea was published by Eimear Nic Lughadha, Eve Lucas, Elizabeth Woodgyer and co-workers. The Myrtaceae of Mount Jaya (6 species including IUCN conservation ratings) has been published. Accounts of Tristaniopsis and Syzygium for the Tree Flora of Sabah and Sarawak are complete and have been published along with 46 taxa new to science in a separate paper.
Herbarium visits made to Paris, Brussels and St Petersburg, Rio de Janeiro and other local Brazilian herbaria by Kew staff and associates have provided an estimated 1,000 new determinations in these institutions. The visits also laid foundations of understanding of groups in subtribe Myrciinae and have been an essential preliminary step towards the production of the generic/infrageneric framework on which Flora Neotropica revisions of the genera will be based.
Comparative Plant Biology (2001-2005)
Molecular systematic work in the Myrtaceae at Kew has two interconnected main objectives, 1) to provide a phylogenetic hypothesis for evolutionary relationships between the 47 genera recognised in tribe Myrteae and 2) to provide a robust generic/infrageneric framework for genera of subtribe Myrciinae on which future baseline plant diversity research on the four currently accepted genera can be based.
Between 2001-2005, c. 130 Myrteae species representing 33 genera have been sequenced for four gene regions (ITS, ETS, psbA-trnH, matK). Preliminary results elucidating subtribal relationships were published in 2005. More detailed collaborative work within subtribe Myrciinae has been carried out in collaboration with the University of Campinas (Brazil), resulting in the sequencing of a further c. 20 species for the above gene regions except matK.
A collaborative programme with the University of São Paulo (Brazil) aiming to resolve generic/infrageneric relationships in subtribe Eugeniinae commenced in 2003. This study has sequenced a further c. 60 Eugenia and Eugeniinae species in 10 genera, for all gene regions except matK.
In excess of 600 new Myrteae sequences have been produced to date.
Morphological studies in subtribe Myrciinae have been carried out in parallel to molecular research. Since 2004, a survey of macromorphological characters has been gathering data from specimens at the Kew, Paris, Brussels and St Petersburg herbaria for a cladistic analysis and detailed review of characters within subtribe Myrciinae. A reduced character set has also been compiled, with which the phylogenetic estimate of tribe Myrteae is being interpreted.
Wood antatomical studies have surveyed 52 Myrteae taxa for 12 characters and 18 Chamalaucieae taxa for 40 characters.
Comparative research on the distribution of phenolic compounds and polyhydroxyalkaloids in the Myrtaceae has shown that they vary in their distribution. Most species of tribe Myrteae contained polyhydroxyalkaloids, whereas their distribution within the non-Myrteae taxa was sparse. In fact, within these latter taxa the polyhydroxyalkaloids were only found in genera belonging to the Leptospermum and Chamelaucium alliances (sensu Johnson and Briggs 1984) and the new DNA based phylogenies place these alliances in a sister clade to tribe Myrteae. To date, only a few of the phenolic compounds present in the 268 species studied have been identified. However, the distribution of isorhamnetin, flavones and flavanones in the genera of Calothamnus and Leptospermum suballiances support DNA-based studies that suggest that these two suballiances are not as closely related as previously thought. The phenolic data also supports the DNA-based phlogeny that divides the Calothamnus suballiance into five clades.
Sustainable Utilisation of Plant Resources (2001-2005)
Taxonomic expertise at Kew supports the Sustainable Utilisation programme in exploring economic potential across the family. Another collaborative research focus is on the insecticidal properties of this understudied group. The project is British Technology Group funded and includes collaboration with the Institute of Arable Crops Research, Rothamsted.
Conservation and Environmental Monitoring (2001-2005)
IUCN conservation assessments were prepared for a total of eleven taxa, seven of which are now published.
A core fields compliant Myrciinae specimen database has been developed which to date comprises c. 6,000 new, georeferenced records, with over 600 type specimens imaged and databased. Myrciinae specimen datasets from the New York Botanical Garden and the Research Institute for Development – French Guiana are being merged with the Kew database. The database contains some 12,000 records.