The monumental task of understanding morphological diversity of large, problematic and challenging British genera has once been again taken up successfully by Tim Rich, this time in collaboration with Walter Scott, an expert on Shetland flora. This book focuses on the British members of Hieracium section Alpestria, which have an unusual distribution, almost restricted to the Shetland Islands in Scotland (although more common in Scandinavian countries than in Britain).
With its beautiful pictures and clear drawings this book will appeal to readers interested in the Shetland Flora as well as those with an interest in hawkweeds. The introductory pages are packed with information about hawkweeds, and particularly section Alpestria. In addition to the descriptions of habitats, conservation and cultivation, there is information about reproductive biology and an attempt to understand the morphological diversity with a Principal Component Analysis (PCA) of 24 morphological traits.
To the untrained eye, all hawkweeds look very similar. Identifying them is a real challenge, but the characters are explained and the abundance of drawings and photographs makes the task easier. The identification keys are divided into two groups: the 26 species of Hieracium on Shetland (including 16 Alpestria species plus ten form other sections), and a smaller key to separate five Alpestria species from the mainland. The geographical separation, although not ideal, should work well thanks to the restricted distribution areas of the species involved.
After the introductory chapters each of the 21 British Alpestria species are well documented with long descriptions, illustrations (drawings, photographs of detail, habitats and distribution maps) and also conservation status and small tips to help separate them from other species.
When dealing with apomictic taxa, there is always the question of whether is necessary to have all the variation named and accounted for. In my opinion, naming the diversity is a crucial starting point for all other research. The main questions of how this restricted group arrived to the Shetland Islands, how it diversified or what its relationships are can only be explained once the diversity and variation have been described. This work represents the foundations for research that can deal with these questions. At the same time, the book is a pleasure to browse.