THE knowledge of the structural characteristics of inanimate materials or living organisms is of primary importance in scientific research. The level at which the structure is studied varies with the object under consideration. The study may start with observations made with the naked eye, and extend to examination with the electron microscope and, for further details, the use of indirect methods.

Plant anatomy, dealing with the structure and development of tissues and cells, and their contents, is of primary importance for all lines of research in plant sciences: morphogenesis, physiology, ecology, taxonomy, evolution, genetics, reproduction, etc.

The continuous development of new and more precise optical and electronic instruments and other direct or indirect methods has made it pos¬sible to reinvestigate previous information on the various tissues and cells, and to carry out research on structures not studied before.

In order to keep the readers of this book informed of the new developments in plant anatomy three updated editions (including this edition) have been published since the appearance of the first English edition in 1967. (The book appears also in several other languages.)

Only part of the results of the new research has been included in the present edition. Many publications, although not less important, are not cited because of the size limitation of the book.

Plant anatomy is a science in its own merit.

However, as mentioned above, plant anatomy is also of basic importance for all lines of research in plant science. As in previous editions, the functional interpretation of anatomical features is emphasized.

In order to retain the main purpose of this book and keep its size within reasonable limits the relation between structure and function is discussed only to such an extent as to stress the relationship between the two and to raise the curiosity of the reader to the problems. For further, deeper know¬ledge of these aspects it is of course advisable to turn to the specific literature.

In the present edition several topics, e.g. cell structure, ecological anatomy, cambial activity and some other subjects have been extended. In all chapters new literature is cited, a number of new illustrations have been added and changes in some previous ones have been made. The Glossary of Terms has been extended and about 550 new references have been added.