Monocots II: Commelinids: key achievements 2006 - 2011

The Monocots II Team generates high impact, multi-disciplinary research in the systematics, evolution and conservation of the commelinds, a major clade of monocots that includes important families such as palms, grasses and sedges.

During the period 2006-2011, RBG Kew’s Commelinid Monocot cross-departmental Science Team has been highly productive. The publication of over 120 research papers and books is indicative of this team’s achievements. Baseline plant diversity research is a prominent strength of the Commelinids Team. The team remains active in fieldwork, resulting in many discoveries. For example, in Madagascar alone, 23 new species of palm have been discovered and described in the past five years, most of them threatened with extinction. Among these is the new genus Tahina, a gigantic fan palm even visible in satellite imagery that dies after flowering and persists in a population amounting to fewer than 100 individuals. The publication of Tahina in 2008 attracted media attention worldwide and earned a “Top Ten Species” award from the International Institute for Species Exploration at Arizona State University. Work on palms in New Guinea, which has also yielded the new genus Dransfieldia and many new species, promises to be every bit as exciting. New genera continue to be discovered in Cyperaceae, including Dracosirpoides and Khaosokia, as well as new species from many parts of the tropics and subtropics. The rediscovery in 2008 of Bulbostylis neglecta, a minute sedge species endemic to St Helena, also attracted significant media attention, having not been seen for over 140 years. It was previously known from only two specimens in the RBG Kew herbarium.

Many floristic, monographic and other taxonomic contributions have been made during the past five years. Floristic accounts have included palms and Typhaceae for the Flora of Thailand, palms for Flora Zambesiaca, grasses for Flora of Arabia and the British Isles (Grasses of the British Isles, 2009) and sedges for Flora of China, Flora of Tropical East Africa andthe British Isles (Sedges of the British Isles 3^rd ed., 2007). Monographs have been published of economically important palm genera, such as Borassus and Areca, as well as fieldguides to palms in Madagascar and New Guinea. Genera Palmarum - the evolution and classification of palms was led and published by RBG Kew scientists in 2008, in collaboration with partners in the USA and Denmark, and is now the standard reference for the family. The book attracted the Annual Literature Award of the Council on Botanical and Horticultural Libraries in 2009.

The Commelinids Team has led recent innovations in biodiversity informatics and eTaxonomy at Kew. With funding from the European Commission via EDIT, an internet portal to palm biodiversity information, Palmweb (www.palmweb.org), has been established and now contains descriptive content for around half of the world’s palm species, including over 3000 images. GrassBase (www.kew.org/data/grasses-db) continues to develop and improve, with some 11,000 descriptions and associated nomenclature available online, representing the most complete online species-level data resource available for grasses. This has been extended through GrassPortal (www.grassportal.org), a collaborative project linking GrassBase names and character data to phylogenetic, biogeographic and environmental data. The success of these new platforms is in part due to RBG Kew’s 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 commelinid researchers regularly contribute. Palmweb and GrassBase form key components of the NERC-funded eMonocot project (www.emonocot.org) and will contribute some 12,000 species pages to this major national and international collaboration.

Research involving construction and use of phylogenetic trees is another primary focus of the the Commelinids Team. Since 2006, 20 papers on palm phylogenetics have been published, including the first complete genus-level analysis of the family, which was constructed using parallel supertree and supermatrix approaches (Baker et al. 2009). This study has facilitated a range of new evolutionary research, such as a recent paper exploring the geography and timing of rainforest origins (Couvreur et al. 2011). Phylogenetic studies in Cyperaceae have particularly focused on tribe Cypereae, for example helping to resolve previously contentious relationships in Cyperus (Simpson et al. 2011). An international collaboration that included RBG Kew described an exceptionally well-preserved fossil mapanioid sedge (Smith et al. 2009), which is now being used as dating evidence in a new, family-wide phylogenetic analysis of Cyperaceae.

Similarly, a dated phylogenetic tree of Haemodoraceae was built to evaluate the biogeography of this family across its two centres of diversity in South Africa and southwestern Western Australia and to investigate timings of major radiations (Hopper et al. 2009). This phylogenetic framework was subsequently used to perform a comparative analysis and ancestral state reconstruction of sand-binding roots in the family, yielding information on function and evolution of these intriguing structures (Smith et al. 2011).

A multi-disciplinary approach involving phylogenetics, population genetics and ecology of the endemic Lord Howe Island palm Howea resultedin the first robustly documented case of sympatric speciation in plants. This research, published in Nature (Savolainen et al. 2006), has been highly cited and is already featured in evolutionary biology textbooks. Through successive grants, most recently from NERC and ERC, the project has been extended to demonstrate that this controversial mode of speciation may in fact have occurred frequently on Lord Howe Island, challenging widely held beliefs about implausibility of such processes (Papadopulos et al. 2011). Next-generation sequencing methods are now being exploited to explore the genomic architecture of sympatric speciation.

RBG Kew has a strong focus on character evolution in commelinids, especially in the large, diverse economically important order Poales and the palm family Arecaceae. The improved phylogenetic background for Poales allows us to address questions about morphological innovations that promoted the considerable species richness of the larger families of Poales, especially grasses. Current foci include evolution of silica bodies in grasses, evolution of floral and seed structures and chromosome evolution in grasses.

The Commelinids Team also pursues a strong conservation agenda. The team is represented on IUCN’s Plant Conservation Subcommittee and also leads the IUCN/SSC Palm Specialist Group. Recently, the IUCN conservation status of the entire Madagascar palm flora has been assessed using GIS and species distribution modeling approaches. The Team is putting plans in place to pursue on-the-ground conservation actions for some of the most threatened species, such as Tahina spectabilis. A similar approach has been undertaken for Cyperaceae in Thailand, which suggests that over 20% of the species are under threat. Initial studies have also been carried out on the potential effects of climate change on Cyperaceae. Bioclimatic modeling of Cyperus rotundus (known as ‘the world’s worst weed’) suggests a significant move of this troublesome species into temperate regions.

Research outputs span the seven strategies of the Breathing Planet Programme, but are especially concentrated in Strategies 1 and 2.

Conferences and workshops

The Commelinids Team was well represented at Monocots IV and Flora of Thailand conferences in Copenhagen in 2008, e-Biosphere in London in 2009, Flora Malesiana Symposium in Singapore in 2010, and the Flora of Thailand conference in Thailand in 2011 At the International Botanical Congress in Melbourne in 2011, RBG Kew staff co-organised symposia on Arecacae, Poaceae and Cyperaceae.

The European Network of Palm Scientists, which was initiated collaboratively by RBG Kew and Aarhus University (Denmark), has met annually since 2001. The RBG Kew palm team always participates at these meetings as well as at the International Palm Conference, held 5-yearly, most recently in Montpellier in 2010.

International Policies

The Teams’ involvement in the World Checklist of Monocotyledons, eTaxonomy and conservation assessment is highly pertinent to the GSPC.

Science Team Leader: Bill Baker