Introduction

The genus Carex includes the sedges that dominate wetlands, pastures, prairies, tundra, and the herb layer of temperate forests. These plants are not only frequently dominant in terms of biomass in plant communities, but they are also prominent in terms of numbers of species. Carex is one of the largest genera in the Canadian flora with approximately 300 species, and consequently almost one-tenth of the native vascular plants of Canada are sedges. In North America there are about 500 species. Worldwide, there may be as many as 2000 species.The results of the recently increasing interest in Carex include regional taxonomic treatments, simplified identification, and many improvements to classification. Basic taxonomic work was supported through the application of chemical, anatomical, and cytological techniques. The first detailed ecological studies of Carex have been completed, and much general ecological information has accumulated. Many scientists are now actively involved in research concerning Carex, and the recent and rapid growth of this research area suggests that a review of the subject will be of value, not only to the researchers involved, but also to the general botanist.On 16 June 1987, the Systematics and Phytogeography section of the Canadian Botanical Association/l'Association botanique du Canada hosted a symposium to review major aspects of Carex research and outline appropriate directions for future study in each area. We are pleased to offer the presented papers to a wider audience as a record of the first international symposium on the systematics and ecology of one of the largest and least well known genera of plants in the temperate regions of the world.