Lamiaceae
Recent Achievements
Collections (2001-2005)
Following the publication of the treatment of Lamiaceae and Verbenaceae in Kubitzki’s Families and Genera of Vascular Plants, the herbarium collection was recurated to reflect the generic and familial delimitation recognised in that work. Our collections now comprise material of 231 of the 237 currently recognised genera: the remaining six genera, five of which are known from the type specimen only, are represented by copies of protologues or illustrations. Recent field work and collection programmes have concentrated on Thailand, Vietnam, Sabah and Brazil.
The living collection of tribe Ocimeae, housed in Technical Glass, was used extensively in the research of the phylogeny, phytochemistry and biological activity of the Ocimeae. Over 150 accessions of Ocimeae were added to the DNA bank, including accessions from most of the living collection.
A new Salvia display, adjacent to the rock garden, has been planted. It is composed of two separate borders, one displaying species from Europe, Africa, Mediterranean, and Central / Eastern Asia, the other focusing on New World species. Salvia is becoming a very popular horticultural plant and this display illustrates both the beauty and diversity of the genus. Again the collection has been used to support research on the phylogeny, phytochemistry and biological activity of the genus, with over 150 accessions of Salvia being added to the DNA bank.
Baseline Plant Diversity Research (2001-2005)
The accounts of Lamiaceae and Verbenaceae and some related smaller families such as Stilbaceae and Nesogenaceae were produced for Kubitzki’s The Families and Genera of Vascular Plants. These baseline accounts involving collaboration of 13 authors under the editorship of Ray Harley, will form the basis of the systematic study of these families for many years to come. In addition, a draft species level checklist, reflecting the current generic and family delimitations of Lamiaceae and Verbenaceae was made available via the Kew internet at the end of January 2006.
The accounts of Lamiaceae for Flora Zambesiaca (c. 260 species) and Flora of Tropical East Africa (c. 310 species) were brought close to completion (to be submitted mid 2006). A major element of this was the account of Plectranthus which comprises around 150 species in the area covered by these Floras. The majority of the species in tropical Africa belong to tribe Ocimeae. The completion of these Floras will provide a firm basis for the study of this much used group in Africa. The Ocimeae are also widely used in Continental South East Asia and a revision of these species was produced in collaboration with Somran Suddee of the Royal Forest Department Bangkok.
A monograph of Lavandula was completed. This addressed a broad audience by not only providing taxonomic species accounts including distributions, conservation assessments and a phylogenetically based classification, but also including information on its horticulture and cultivars. The illustrations were awarded a Royal Horticultural Society Gold medal.
Baseline work on the subfamily Viticoideae begun in this period with accounts of Vitex produced for New Guinea, the Pacific and Malesia. Revisionary work on S American Verbenaceae was completed with the monograph of Stachytarpheta in Brazil.
Comparative Plant Biology (2001-2005)
A molecular phylogeny of tribe Ocimeae was produced and used as a basis for discussion concerning biogeography and the distribution of morphological, phytochemical and palynological characters within the group. This involved the collaboration of team members from the Molecular Systematics Laboratory, Plant Anatomy Section and the Biological Interactions Section of the Jodrell Laboratory, horticultural staff of the Technical Glass unit, Herbarium staff and one Thai and one Kenyan PhD student trained at Kew. The phylogeny is currently being used as a basis for further investigation of the phytochemistry of Plectranthus.
Research with a wide range of external collaborators on flavonoids, diterpenoids and iridioids, to examine relationships within genera across the Lamiaceae and in the broader Lamiales, has revealed interesting results. Within the economically important genus Ocimum, flavonoids have been used to characterise cultivars; specific flavonoids and essential oils differ among species of Nepeta and are currently being mapped onto a DNA-based phylogeny of the genus: within the Lamiaceae, caffeic acid ester derivatives, nepetoidins A and B, were found to be present in a very large percentage of species in the subfamily Nepetoideae and absent from all the other subfamilies; and within the order Lamiales, flavonoids and iridoids have been used along with molecular phylogenies to explore relationships of the members of the newly defined Plantaginaceae, which now contains many genera which formerly belonged to the Scrophulariaceae.
Work has continued on floral morphology, anatomy and embryology of Lamiaceae, including related taxa of the order Lamiales. Paula Rudall has successfully jointly-supervised with Robert Scotland (University of Oxford) two DPhil students in this field (Elizabeth Moylan and Alex Wortley), and published three papers on floral anatomy and one on phylogenetics of Lamiales. These studies focus on ‘rogue’ genera (Aragoa, Hemigraphis and Thomandersia) that were previously considered to be phylogenetically isolated within Lamiales, and examine floral characters to address their relationships.
Sustainable Utilisation of Plant Resources (2001-2005)
Many Lamiaceae are used economically, culturally and in traditional medicine. During the five year period, 1,280 species use reports were produced. Holy basil (Ocimum tenuiflorum) was selected as one of the 25 plants for the Plant Cultures web-based project. The project highlights the traditional uses of these plants in Southern Asia and modern uses of these plants by Asian communities in England. Several papers have been produced with collaborators in Spain and Italy on the antifeedant activity of diterpenoids from species of Ajuga, Scutellaria and Teucrium that have anti-insect activity.
Research publications have also explored the use of Salvia derived compounds in cosmetics, the treatment of Alzheimer’s disease and memory disorders, diabetes, and as a replacement for bear bile in traditional Chinese Medicine.
A review of the ethnobotanical uses of Plectranthus, in collaboration with Catherine Lukhoba, University of Nairobi, revealed that most medicinal use was concentrated in two clades of the genus.
Conservation and Environmental Monitoring (2001-2005)
Preliminary conservation assessments continue to be produced with accounts of species in Floras, revisions and new species accounts. Significant numbers of species level assessments were produced for SE Asian Ocimeae (77); Stachytarpheta (79) and Lavandula (39). An influential paper outlining the use of herbarium specimen data in producing conservation assessments using Plectranthus in E Africa was published. This outlines how distributional data can be used to assess species using the IUCN categories and criteria and discusses some of the associated problems.