Monocots III: Orchids: key achievements 2006 - 2011

The Monocots III (Orchid) Team produces high impact, multi-disciplinary research in systematics, evolution and conservation of the orchid family, Orchidaceae, the largest angiosperm family.

During the review period, Kew’s Orchid cross-departmental Science Team has been highly productive. Publication of over 100 research papers, many higher-profile, and books took place. Baseline plant diversity research is a prominent strength of the Orchids Team, who are active in fieldwork, resulting in many discoveries. For example, André Schuiteman co-discovered several new orchid species in Laos, including the showy Holcoglossum calcicola. More fieldwork in Papua New Guinea and Cambodia is planned. Many floristic, monographic and other taxonomic contributions have been made during the past five years. Floristic accounts include the magnificent two volume The Orchids of Mount Kinabalu (Wood, J.J. & al. 2011) and a Field Guide to the Orchids of Madagascar (Cribb, P.J. & Hermans, J. 2009). Numerous new species and systematic findings were published in various journals. The peer-reviewed Malesian Orchid Journal is edited at Kew by Jeffrey Wood. A key monograph has been published of the horticulturally important genus Cymbidium (Du Puy & Cribb, 2007).

The monumental series, Genera Orchidacearum (GO; edited by Alec Pridgeon, Mark Chase, Phil Cribb, all from Kew, and Finn Rasmussen in Copenhagen), a six-volume treatment of all genera of Orchidaceae, has progressed well during the five-year period, with volume 5 (Epidendroideae, part two, 585 pages) published in 2009. This volume included the treatment of the large Neotropical Oncidiinae (by Mark Chase), a subtribe in which generic limits have long been highly contentious. The last volume is well underway and should be published in late 2012.

Orchidaceae are one of the very large families treated by the World Checklist of Monocotyledons, a taxonomic web resource of particular significance to the delivery of the Global Strategy for Plant Conservation to which Kew’s orchid researchers regularly contribute. The American Orchid Society and the Royal Horticultural Society have both agreed to use the World Checklist treatment of orchids as the basis for their database of orchid hybrids, so this means that horticultural taxonomy of orchids is kept parallel to that used in science (this has not always been true previously). In turn, the GO treatment of orchid genera is used as the standard for the World Checklist.

Research involving use of phylogenetic trees is another primary focus of the Orchid Team. Since 2006, 28 papers on orchid phylogenetics have been published, including a large analysis with a single-copy nuclear gene, Xdh (Górniak, Paun and Chase. 2010). Phylogenetic studies in Orchidaceae have particularly focused on tribe Orchideae, for example helping to confirm previously contentious relationships in several genera (Bateman et al. 2009; Inda et al. 2011), subtribe Oncidiinae (Chase et al. 2009), subtribe Cranichidae (Salazar et al. 2009), subtribe Laeliinae (van den Berg et al. 2009) and subtribe Angrecinae (Micheneau et al. 2008). DNA barcoding of an orchid flora was also the subject of a Darwin Initiative Project to (V. Savolainen) for training and assisting CITES regulation in Costa Rica (Lahaye et al. 2009). Also a point of focus was hybridization and polyploidy in Polystachya (a pantropical genus with highly problematic infrageneric taxonomy; Russel et al. 2010a,b) and Dactylorhiza (Pillon et al. 2007; Paun et al. 2010). In Paun et al. (2010), epigenetic variation in allotetraploids and ecological traits have been demonstrated to be linked, the first time these connections have been investigated. Phylogenetics and genome size evolution in Orchidaceae have also been studied (Leitch et al. 2009; Kahandawala 2009).

Papers published on the effects of fungal and insect mutualisms on orchid speciation and coexistence (Waterman et al., 2011; American Naturalist), on onstraints to nutritional modes in orchids (American Journal of Botany), and on fungal specificity bottlenecks during orchid germination and development (Bidartando and Read, 2011; Molecular Ecology), and on mutualistic breakdown and cospeciation in Burmanniaceae and Triuridaceae (Proceedings of the Royal Society B). The Team have published a review on orchid pollination and mycorrhizas (Journal of Experimental Botany) and also given invited talks at the Science Museum, at Birkbeck College, at meetings of the Botanical Society of America and the Mycological Society of Japan and at a NordForsk Nordic Researcher Network meeting.

Pollination biology has also figured prominently in this period. For the first time, crickets have been shown to be the primary pollinators of an angiosperm, in this case an orchid from Reúnion (Micheneau et al. 2010) pollinated by a new species of rusty cricket (Hugel et al. 2010), which was one of the “Top Ten Species” awarded by the International Institute for Species Exploration at Arizona State University. Ongoing work has also focused on deceit pollination by mimicry of Malpighiaceae in species of Oncidiinae (Powell, Savolainen and Chase, submitted). Further ongoing work in mimicry by orchids is focusing on the ecology and evolution of the peculiar mushroom mimicry exhibited by the genus Dracula (Pleurothallidinae; Dentinger et al. in progress).

The colourful and unusual flowers of orchids remain a research focus for studies in character evolution at Kew. Six papers were published on orchid floral morphology and development during 2006−2010. These studies focused on European terrestrial orchids and included comparative labellum micromorphology of the sexually deceptive genus Ophrys (Bradshaw et al. 2010) and spur development in selected Orchidinae (Box et al. 2009; Bell et al. 2009). Ongoing studies on orchid flowers form part of broader collaborative programmes on monocot flowers in general and evolution and development of structural colour in angiosperms.

Orchid seed conservation biology was advanced mainly through a three-year Darwin Initiative Project (£220 k) ‘Orchid Seed Stores for Sustainable Use (OSSSU).’ Initially networking 15 countries in the Americas and Asia, OSSSU now connects >30 institutes in 25 countries. Seeds of >300 species across >100 genera have been conserved in-country and in vitro germination protocols developed for >150 species. OSSSU produced 17 publications (papers or book chapters), 9 newsletter articles, >30 newspaper or web articles; and >30 presentations (talks and posters) were given at conferences.

The Orchid Team also pursues a strong conservation agenda. Taxonomic exaggeration in European native orchids, genetic variation and implications for conservation have been examined (Pillon et al. 2006; Pillon and Chase 2007). The team is represented on IUCN’s Plant Conservation Subcommittee and also leads the IUCN/SSC Orchid Specialist Group. In a collaborative project with the World Conservation Monitoring Centre, 153 redlist assessments for European orchids were completed during the period covered by this report. Orchids figure strongly in the conservation genetics programme, with a portfolio of projects from the UK and abroad (e.g. Ophrys: Devey et al. 2009; Cypripedium: Fay et al. 2009; Cephalanthera: Micheneau et al. 2010; Epidendrum: Pinheiro et al. 2010; Pseudorchis: Duffy et al. 2011).

Threatened European and Madagascan orchids have been propagated in the Conservation Biotechnology Unit by in vitro seed germination for recovery, reintroduction and cryopreservation research. Ongoing work is focused on living collection development for taxonomic identification, sustainable utilisation and restoration projects.

Conferences and workshops

The Orchid Team was well represented at the Monocots IV conference in Copenhagen in 2008. Other conferences attended have included International Orchid Conservation Congress in Costa Rica (2007), at which Mark Chase was awarded the Premio Jardin Botanico Lankester for contributions to the science of orchids, the Botanical Society of America Conferences in 2006 (Chico, California), 2007 (Chicago, Illinois), 2008 (Vancouver, Canada) and 2010 (Providence, Rhode Island). At the International Botanical Congress in Melbourne in 2011, Kew staff co-organised a symposium on orchid phylogenetics/population genetics and participated in two others, as well as presenting several talks on techniques for studying orchid evolution at a one-day workshop organized on the last day of the IBC. The OSSSU (above) held three capacity building workshops and cascade training reached five technicians, 104 undergraduate, 10 masters (and equivalent experience) and 3 PhD students. OSSSU leader (Hugh Pritchard) was awarded best lecture at the International Seed Testing Association’s triennial congress in Germany in 2010. Mycological research concerning orchids was presented in a special symposium on insect-fungus interactions at the XVI Congress of European Mycologists in Greece (2010) and at the British Mycological Society Autumn Open Meeting, held at Kew (2010). Andre Schuiteman (HLAA) gave an oral presentation on the Dendrobium project at the 8th International Flora Malesiana Symposium (2010) in Singapore. Paula Rudall gave lectures on orchid floral traits at the 2009 SFO Orchid meeting (Montpellier, France) and the 2009 and 2011 UK Hardy Orchid Society Autumn meeting. Members of the team organized two conferences on orchids at Kew, in 2006 to mark the retirement of Phillip Cribb from the Herbarium and in 2007 to mark the tercentenary of Linnaeus’ birth. The latter resulted in a special issue of Annals of Botany (Vol. 104, Part 3).

Research spans the Breathing Planet Programme strategies, but we make particularly significant contributions to strategies 1, 4, 5 and more recently to 6.

International Policies

The Orchid Team’s involvement in the World Checklist of Monocotyledons, eTaxonomy and conservation assessment is highly pertinent to the GSPC target 1.

Living collections

More than 2,000 orchid species are being cultivated at Kew in the Tropical Nursery. These specimens are an important source of material for morphological, anatomical and phylogenetic research by the Orchid Team. Members of the Team regularly visit the living collections to add or verify identifications.

Science Team Leader: Mark Chase