National Herbarium is the major national institution responsible for authentication of plants of Sri Lanka. The National Herbarium actively involved in plant exploration, identification, specimen preparation, also documentation and revision of revision of floral wealth of the country. By surveying and inventorying plant genetic resources especially for Food and Agriculture, it contributes significantly to the development of the national economy.

It provides facilities to the local and foreign researchers to carry out taxonomy related research work also serving the National Plant Quarantine and Customs to identify plants correctly when legal matter arises in plant and plant material import and export. Recently it has also being recognized as National Red Listing Authority of plants in Sri Lanka. The National herbarium engaged in exchange of knowledge and specimens with the herbaria and research institutes of the other parts of the world.

At present scientists in the National Herbarium involve in studying lower plants diversity of Bryophytes and Lichens. A special project on compiling information on Crops Wild Relatives (CWR) is also in progress which helps to identify clearly which wild crop relatives and wild plants for food and Agriculture need to be protected in-situ.