The main contributions were by P. M. Jørgensen, with additional sections from B. Büdel (Cyanophytic algae), T. Tønsberg (Lobariaceae) and O. Vitikainen (Nephromataceae and Peltigeraceae).
This long-awaited book will be of great interest world-wide as it deals with Scandinavian lichens containing blue-green photobionts. In particular the identification of the small, black species has been a particular problem for many years, and this thorough treatment is most welcome.
The book commences with a ‘Guide to the Families’ and provides a single-page, simple key. A map is then given, of Norway, Sweden, Finland, Denmark, Iceland and associated islands, together with their geographical provinces, abbreviated by name, but not given in full so reference to an atlas is needed. All 217 species are dealt with alphabetically by family and then by genus. This makes the use of the book slightly inconvenient, as there is, therefore, a need to consult the contents list to locate a particular genus. Each family starts with a brief description, then a key to its constituent genera. Genera are treated similarly, with citation of type specimens and dates, and relevant literature. The generic descriptions are brief, with mentions of chemistry where applicable and notes on world distribution. The keys to species have a generous number of characters in each dichotomy and seem to work well. Individual species are then dealt with by listing types, synonyms, relevant descriptions, chemistry, habitat, distribution and any additional notes on easily confused species, etc. The overall style is brief but satisfactorily succinct and to the point.
All species are illustrated, by a generously sized, 6 ×8 cm colour plate, which is repeated in an accompanying CD-ROM. This is, in some cases, a first attempt to illustrate many of these taxa, especially the smaller ones. In general the photographs are of a high standard, and it is quite possible to identify many species simply by looking at the photographs. However, some of the smaller species would have been better served by using a higher magnification. It is noticeable that many have a brown colour caste and are obviously photographs of herbarium material, some of it rather old. It is unfortunate that genera like Peltigera, Nephroma and Sticta were not supported by fresh, damp specimens where colours can be a useful aid to their identification. However, it is extremely valuable to have photographs of the venation and rhizines on the undersides of Peltigera. While most photographs are very good, those of the smallest species can be hard to define. For example, Parmeliella parvula thalli are hardly visible in the photo and cannot easily be distinguished from the host twig. The photograph of Lichina pygmaea has an adequately large magnification but the much smaller L. confinis has a small magnification in which individual thalli are hardly visible. The photographs and maps are in alphabetical order by genus and species.
Each species is illustrated by an individual distribution map, though the location dots denote provinces of each country and can only approximately be related to map co-ordinates. Common names are given, where they exist, in the language of their host country. References to illustrations in other publications are also cited.
One major problem with the cyanolichens lies in the identification of their various photobionts. As the cells and/or filaments of cyanobionts are frequently malformed within the lichen thallus, an accurate identification can only be done after isolation in culture, a difficult process. However, cyanobionts need to be identified in order to determine the family, and in some cases the genus, and a simplified, summarized scheme is here provided following that of Büdel (Reference Büdel and Reisser1992).
The authors indicate that some taxonomic treatments still remain provisional. Forsell (1885) provided the first treatment of the small, black species from Scandinavia, but this study is now largely outdated. Subsequent authors have surveyed individual families but this book provides the only overall, in-depth treatment of these and their individual species. The Leptogium account is well-defined and after many years of confusion, the smaller species can now be confidently identified. A useful treatment of the chemistry of Peltigera is provided, with details of the difficult series of terpenes. Only two species of Porocyphus are given in this flora and there are obviously still problems to be resolved here. Porocyphus coccodes in this flora closely resembles the entity P. leptogiella as understood in Britain, while the British entity known as P. coccodes isn't included here (areoles plane and black). Placynthium also presents particular problems in the British Flora and some readers may take issue with some descriptions in this book.
An appendix details ‘Nomenclatural novelties’. This is an important section on the designation of type specimens and the names adopted in this treatment, often with source quotations giving the background to some of the names. It is very thorough and suggests most type specimens have been systematically examined. The book closes with indices to specimens used for photographs and synonyms. There is no general index, either to genera or species, and curiously, there is no overall list of the references which are dealt with in the text. The volume is dedicated to the tutors of the authors, Prof. Rolf Santesson on the occasion of his 90th birthday, and Prof. Dr Aino Henssen.
The book is well produced with generous margins and there seem to be few mis-spellings apart from Peltigera aphthosa on the plate, page 192. Although this is the third volume of the Nordic Lichen Flora, the companion volumes detailing Caliciales (vol. 1) and Physciaceae (vol.2) are, surprisingly, nowhere indicated.
Finally, this is a most important volume and the authors should be congratulated on the high academic standard and precision, particularly relating to the citation of sources of names. The volume strongly emphasises the critical, and frequently overlooked, importance of the typification concept and its continuing and fundamental value in modern taxonomy.
