Monocots II: Commelinids
Background
Palms
Palms are ranked among the three most economically important plant families. In some parts of the tropics they supply nearly all the necessities for subsistence communities, providing food, material for housing, clothing, fuel and ornament. Some palms (e.g. oil palm, coconut, date) have become major crops, and there is potential for the development of further palm crops for agriculture and forestry. Like all other plant families in the humid tropics, palms are severely threatened by habitat destruction. They are further threatened, however, through targeted exploitation for specific products (e.g. palm hearts, rattan), thereby endangering both the survival of the palm species and indigenous cultures. Certain species of great economic importance continue to be heavily exploited in the wild and are becoming extremely rare.
Kew holds an unrivalled collection of palm resources. The palm herbarium houses 30,000 specimens, including a high percentage of types and historical material. It is the most extensive and representative collection of palms in any herbarium, and an invaluable resource for identification of new material. This material is augmented by 1,200 specimens in spirit, and extensive photographic and illustrative collections. In addition, the DNA Bank in the Jodrell Laboratory contains 672 palm extractions respresenting 141 genera and 400 species. Living palms are especially well represented at Kew by 536 accessions, comprising 110 genera and approximately 300 species, placing Kew among the ten most species rich public palm collections in the World.
Until the mid-1970s, little research on palms was conducted at Kew. Over the last 30 years, however, Kew’s palm group has taken a global lead in research on the diversity, evolution and comparative biology of palms. Co-ordinated from the Herbarium, palm research at Kew is inter-disciplinary and currently involves staff based in four departments (Herbarium, Jodrell Laboratory, Seed Conservation Department, Horticulture and Public Education). Primary strengths lie in floristic and monographic research, especially of Malesian, African and Madagascar palms, higher level systematics and evolution, palynology and micromorphology in general. Most significant is the benchmark monograph of the family, Genera Palmarum (Uhl & Dransfield 1987), a Kew/Cornell University collaboration, which has spawned extensive new research throughout the world. A decade of molecular phylogenetic research, in which Kew has played a leading role, and the wealth of comparative research since 1987 has prompted a dramatic revision of the classification of palms, which will form the basis of new edition of Genera Palmarum, co-authored by three Kew staff and three collaborators, to be published in 2007.
Conservation and sustainable use are also prominent in the Kew research programme, for example in systematic studies of seed storage characteristics, targeted species conservation projects, and research products for the rattan industry. The palm team collaborate extensively with partners overseas and maintain a high international profile, organising and contributing to conferences and workshops in Kew and abroad, supervising postgraduates in the UK and abroad, training overseas counterparts, and co-editing Palms, the journal of the International Palm Society.
Grasses
Economically grasses are the most important plant family, providing 90% of the world’s food as cereals and covering 30% of the land surface with natural grassland. Grasses serve not only the developed but also the developing world where many species are important as minor cereals and famine foods. In the tropics bamboos often provide most of the daily necessities for rural communities. Apart from their practical uses grasses have ever-increasing popularity in horticulture. Most recently, interest in grasses has expanded to include their use as raw materials for a wide range of commercial products and as a source of biomass for power.
Grass research at Kew dates back to 1854 and has been undertaken by high-profile researchers including G. Bentham, J.G. Hooker, O. Stapf, N.L. Bor, C.E. Hubbard, W.D. Clayton and S. Renvoize. Our collections of grasses are unrivalled. The Herbarium houses c. 350,000 grass specimens of which an estimated 11,000 are types. In parallel are collections of illustrations, photographs, spirit and carpological material in the Herbarium and anatomy slides in the Jodrell Laboratory . In the DNA bank we have 248 collections representing 102 genera and 205 species. We also have 1,300 living collections, many of which are grown in areas of the Gardens dedicated to grasses and bamboos respectively. In the Millennium Seed Bank there are 2,783 seed collections. The size and scope of all these collections ensure that Kew is recognised as a world centre of excellence in grasses, attracting a large amount of material for specialist naming.
Our research focuses on floristics and monographic work, especially in tropical Africa China, Southeast Asia and tropical South America, with collaborative projects both within and beyond Kew. Molecular and anatomical studies are helping to resolve ambiguities and collaboratively develop a phylogeny for the family. Genera Graminum (Clayton & Renvoize 1986) is the benchmark Kew publication which has formed the basis of modern grass classification. This is now under revision to incorporate recent phylogenetic work. We have also pioneered the development of global species and nomenclatural databases in grasses.
Sedges
Sedges have economic importance going back into antiquity, highlighted by the role of papyrus (Cyperus papyrus) in early Egyptian society. Today their importance is wide-ranging, from the problems they present as weeds (Cyperus rotundus has been termed the world’s worst weed) to their considerable number of uses – providing materials for basketry, matting, construction (particularly thatch), perfumery, medicine and fuel, as well as food and animal fodder. The numbers of species of horticultural interest has increased, especially in recent years, coinciding with a general interest in ‘ornamental grasses’. Their importance has often been under-estimated, but there is no doubt that they play a significant role in many local economies, particularly in the tropics. Sedges are also important indicators of environmental damage, especially to aquatic habitats. They are particularly sensitive to the lowering of water tables and/or water pollution and there are observable declines in many species. Some genera are threatened by forest destruction and the prevalence of narrowly endemic taxa within these genera may mean that some of them are now extinct.
Research on Cyperaceae has been undertaken at Kew since the 1880s with a succession of botanists working on the family including C.B. Clarke, E. Nelmes and S.S. Hooper. As a result the collections are unrivalled in size and scope. There are c. 110,000 specimens in the Herbarium including all but one of the genera currently recognised and nearly all described species; over 6% of the specimens are types. These are complemented by numerous ancillary collections of spirit and carpological material, illustrations, photographs and anatomy slides, together with 142 living collections, representing a wide range of genera, located throughout the Gardens. The Millennium Seed Bank has 628 seed collections and we also have 400 DNA collections in the DNA bank representing 69 genera and 254 species. As one of only a handful of institutes that actively specialises in Cyperaceae systematics, Kew is recognised as a world leader, resulting in a continuing influx of material for specialist naming from all parts of the world as well as researchers wishing to study the collections.
Our research comprises floristic and monographic studies, undertaken as collaborative projects within Kew and elsewhere. We are taking a global lead in resolving the phylogeny of Cyperaceae: pioneering molecular and pollen studies undertaken at Kew have provided the basis for developing a phylogenetic assessment of the family. Nevertheless, many ambiguities still exist, both within the family (at tribal level and below) and in understanding sister-group relationships (particularly the nature of the relationship with Juncaceae).
Other families
Other Commelinid families are well represented in all our collections with, for example, over 800 bromeliads and nearly 300 gingers in the living collections. Research is undertaken by Kew staff and associates on a number of families including Bromeliaceae, Eriocaulaceae, Haemodoraceae, Juncaceae, Pontederiaceae, Zingiberacaeae and Xyridaceae. Such work includes surveys of critical characters, floristic and monographic accounts of selected taxa and molecular work.