This handbook has not considered all fresh-water aquatic plants, nor all possible uses for them. This is probably, in part, because some publications may have inadvertently been overlooked, and in part because many ways of utilizing aquatic plants have yet to be published. It is to be hoped that readers of this book who notice such omissions will publish what they know and draw attention to valuable but perhaps not widely known publications so that the information they contain can, in due course, be collated and made available for all who are concerned with the problems of aquatic plants and the potential ways in which they can be put to use.
The U.S. National Academy of Sciences is performing valuable service in this way. Frequent reference has been made in this handbook to their 1976 publication. Those who are not specialists in this field, and who avail themselves of the wealth of information complied by Sculthorpe (1967), may be surprised at the large numbers of aquatic plants which exist and their wide diversity of form, function and habitat. Sculthorpe's book will remain an essential reference for many years, and a study of its pages will reward anyone who has marvelled at the charm and beauty of plants which live in water. An admiration which may reluctantly be acknowledged even by those who have struggled to force canoes and boats through dense mats of choking water weeds, or have suffered the losses, ill health and danger from explosive occupation of water by some exceptionally vigorous plants. In these circumstances - and millions of people have to endure them-it is not easy to share the admiration of water plants held by those who have fortunately not had to suffer from them.
Sculthorpe writes (p.503): “In India, China and Japan several decorative water plants have been held in the highest esteem sinc ethe earliest times. The immense admiration of the beautiful flowers of lotuses and waterlilies, above all others, is reflected in their frequent portrayal on fabrics and tapestries, pottery and metalwork, monuments and tombs, temples and public buildings, and in their adoration in prose and verse.”
This admiration spread to the western world where water gardens were developed to a high form of art. A consequence of this has been the distribution round the world of many water plants, some, like the water hyacinth - the most notorious of all - spreading prolifically and dangerously.
Now it seems the circle may have almost completely turned. Pampered and admired plants became pests and now, with greater insight, are again seen (but for different reasons) as valued and potential assets to mankind.
