Floristic and inventory work
Floral evolution in orchids
Evolution of floral colour and mimicry
Population genetics, conservation and re-introduction
World Orchid Checklist
• Evolutionary studies (Kew
contact: Mark Chase)
Until recently orchid classification has been poorly understood because of the lack of a fossil record, the large number of species (many of them rare or inaccessible), and a historical emphasis on characters related to floral morphology. Circumscription of genera, subtribes, tribes, and subfamilies and the relationships among them were unclear because of homoplasy in morphological and anatomical features. Phylogenetic research using DNA sequences, largely based at RBG, Kew, is now unravelling the complex picture at every taxonomic level. Kew’s DNA bank contains DNA of many hundreds of orchid species.
• Genera Orchidacearum (Kew
contact: Alec Pridgeon)
Genera Orchidacearum is a multi-disciplinary and multi-authored approach to producing a new classification of the orchids that emphasises monophyly. Evidence from molecular analyses is being integrated with morphological, ontogenetic, anatomical, cytological and biochemical evidence to produce a new phylogenetic classification of the orchids. A new subfamily, the Vanilloideae, has been recognised. Tribal, subtribal and generic delimitation has also been substantially revised. Three volumes (of six) have been published by Oxford University Press, a fourth is nearing completion. The project is scheduled to be completed in 2006-7.
• Monographic work (Kew contact:
Monographs of genera of horticultural and conservation significance are prepared for The Botanical Magazine Monograph Series and for publication by Kew as a separate series. Genera, such as Cypripedium, Dendrochilum, Coelogyne, Paphiopedilum, Pleione and Cymbidium have been published in recent years.
• Floristic and inventory work
(Kew contact: Phillip Cribb)
The rich herbarium and extensive living collections of Old World orchids are critical for our improved understanding of the orchids of the region. Kew’s long-standing commitments to the floras of tropical Africa were completed in the 1990s and this has allowed us to refocus attention upon tropical Asia, which has the richest diversity of orchids in the Old World. In collaboration with the Rijksherbarium in Leiden and institutes in Southeast Asia, we have been preparing floras, checklists and monographs for the Flora Malesiana orchid treatment. Orchids of Bhutan, The Orchids of Peninsular Malaysia and Singapore, The Orchids of Java, The Orchids of Sumatra, The Orchids of Sarawak and four volumes of The Orchids of Borneo have recently been published.
The completion of the Flora Malesiana account, estimated at 8000 or more orchid species, has led to agreement that a conventional floristic treatment is impractical. Two CD-Roms of New Guinea orchids have already been published by Rijksherbarium, University of Leiden with Kew’s collaboration. Further CDs are in the pipeline.
The Orchids of Madagascar, an up-to-date checklist and bibliography was published in 1999. A Field Guide to Ethiopian Orchids has also recently appeared.
Completed and current monographic work suggests that from 10 to 30% of the orchids of the tropics have yet to be described. Checklists and floras eg. those for Madagascar, Mt Kinabalu (Sabah), Borneo and Sulawesi, are a first step to cataloguing the floras. Our knowledge of Old World orchids is contributing towards Genera Orchidacearum. Our understanding of the orchids of the region has been put to good use for conservation work and for reintroduction programmes.
• Floral evolution
in orchids (Kew contact: Paula Rudall)
Orchid flowers are unusual because they are bilaterally symmetrical, in contrast to the radially symmetrical flowers of most other lilioid monocotyledons, and because their stamens and style are fused into a complex structure termed a gynostemium. Occasional spontaneous mutations of orchids flowers display radially symmetry and displaced floral organs. This research programme uses evidence from floral anatomy and ontogeny, and from detailed records of naturally-occurring floral mutations to examine the evolution of the complex orchid floral structure, and the nature of the gene products that regulate it.
• Evolution of floral colour and mimicry
(Kew contacts: Vincent Savolainen
Flower diversity culminates in the orchid family with their highly specialised pollination biology. Approximately one third of all orchid species do not reward their pollinators and therefore rely on their ability to mislead them through some form of deception; one such example is the hypothesis that they mimic neighbouring plant species that reward pollinators. If mimicry does operate, however, it might not be easy to distinguish which are the model species. Our work utilises high-tech image analysis equipment to measure colour spectral reflectance of flowers and uses a model of insect vision to calculate convergence/divergence indices between species as seen through insect's eyes. This work will help our understanding of the evolution of floral colour and address whether mimicry operates in plant communities that include deceptive orchids.
• Population genetics, conservation
and re-introduction (Kew contacts: Mike
Fay and Margaret Ramsay)
The Sainsbury Orchid Conservation Project, established in 1983 to propagate and reintroduce endangered British orchids, has the backing of English Nature, The Royal Society for Nature Conservation and the County Naturalists Trusts. It continues to research propagation methods for re-introduction programmes in the UK and abroad. More than 40 British, European and North American orchid species have been successfully propagated. Five endangered British species: Cypripedium calceolus, Orchis militaris, O. simia, Himantoglossum hircinum, Liparis loeselii, have been successfully reintroduced into selected sites as well as more common species of Anacamptis and Dactylorhiza. Cypripedium calceolus and Liparis loeselii have recently flowered in the wild from re-introduced seedlings. Two staff sit on English Nature’s Cypripedium Committee and Kew is joint Lead Partner for delivery of UK Biodiversity Action Plans for C. calceolus and L. loeselii.
The techniques developed in the project have been used successfully elsewhere to raise seedlings for conservation and horticultural purposes. An orchid micropropagation techniques course was given in Mexico at the request of the Latin American Association of Botanic Gardens and demand for information is high. Derivative programmes have been developed abroad e.g. Denmark, The Netherlands, Switzerland and the USA. It also provided the inspiration for Hanne Rasmussen’s recently published book Terrestrial Orchids: From Seed to Mycotrophic Plant. New techniques and developments are occasionally published through the Micropropagation Newsletter.
Seed of rare tropical species in the Living Collection are routinely distributed to other interested parties and for exchange. In a project funded by the Weston Foundation, the first steps to establishing a nursery in Madagascar have been completed successfully in conjunction with the Parc de Tsimbazaza, the national botanical garden. The aim is to provide in vitro plants raised from seed to enrich the educational and scientific collections at Tsimbazaza, for possible reintroduction of certain rare species. It is hoped that sale of excess repatriated plants will help to raise funds there to help research and perhaps eventually provide alternative income sources to collecting in the wild.
The Conservation Genetics Unit (established in 1996) has used a range of genetic fingerprinting techniques to investigate population genetics of orchids, and the data collected (presented as conservation genetics reports) are being used to inform conservation management of endangered species, largely in the UK but also in collaboration with colleagues in Sweden, the USA and elsewhere. The same techniques are also being used to investigate relationships within species complexes where DNA sequence data are not sufficiently variable, notably in Dactylorhiza.
Phillip Cribb is the chair of the IUCN/SSC Orchid Specialist Group; other staff are members. Conservation information on orchids is also provided for CAPS, CITES, and CBD work. Advice on orchids is regularly provided to the CITES Scientific Authority. Two volumes of the CITES Orchid Checklist were published in the period.
• Seed conservation (Kew contact:
Hugh W. Pritchard and Chris Wood)
The Seed Conservation Department has been involved in orchid seed germination and storage research since the early 1970s. The initial focus was on the development of appropriate media for the asymbiotic germination of a broad range of species, which resulted in the production of a tremendously useful and popular technical guide (Thompson 1977; Growing orchids from seeds, RBG Kew). In the 1980s the emphasis was on innovations in seed storage, using cryopreservation, and in viability testing, using the vital stain fluorescein diacetate. In addition, the first international meeting on orchid conservation methods was organised, resulting in a book (Pritchard 1989: Modern Methods in Orchid Conservation, Cambridge University Press). Recent investigations have pioneered a system of simultaneously cryopreserving orchid seeds with their fungal symbionts. Banking and viability studies have also been progressed recently under the auspices of the Millennium Seed Bank Project, particularly with collaborators at Kings Park (Perth, Western Australia) and the National Museums of Kenya (Nairobi, Kenya). We currently seek to promote the ex situ conservation of orchid seeds through the IUCN Orchid Specialist Group and to enhance knowledge of seed longevity across the family.
• World Orchid Checklist (Kew
contact: Rafaël Govaerts)
The World Orchid Checklist includes about 24,000 accepted species and 65,000 names in total. The data included are name, place of publication, synonymy, and global distribution. These data can be accessed via the World Checklist of Monocotyledons. This can be used to check spelling and synonymy of orchid names. The data follow the generic concepts of Genera Orchidacearum and are part of a wider project, the Electronic Plant Information Centre (ePIC), meant to bring together knowledge and information on plant species. This will eventually provide illustrations, local uses, molecular data, conservation ratings, and much more.
The database is updated regularly as about 800 new names are added each year. With this continued annual increase, the number of orchid species may eventually reach 30,000 or more. The currently accepted classification of the orchids is also in a state of flux as new evidence, mainly from DNA studies, is incorporated into an increasing data set that forms the basis of assessments of generic and higher affinities. The online checklist will, however, try to provide a current taxonomic concept.
Searches will eventually be possible on the different elements of the checklist so that, for example, regional lists can be made. Such regional lists may be helpful in trying to determine plants from particular areas or for assessing the conservation status of a taxon in a particular region.
Micropropagation of orchids (principally orchid seed germination) is
used to achieve several objectives:
To grow plants to augment, restock and reinforce Kew's living collections;
For research purposes - including refining propagation techniques and provision of material for a variety of other research projects both within Kew and external organisations;
For conservation - propagating directly for re-establishment and other conservation initiatives;
Providing training, capacity building and educating a wide range of recipients in the techniques used in the laboratory and collaborative projects.
For further information, please see the micropropagation pages.