Building on the success of the first edition and featuring contributions from leading experts in the field, this expanded and thoroughly revised second edition provides an indispensable guide to the freshwater and terrestrial algae of the British Isles. It is an up-to-date account of and identification tool for more than 2400 algal species (excluding diatoms), highlighting their wider distribution around the world. Detailed descriptions are fully illustrated with clear line drawings and photographs including 190 full-page plates, eight of which are full colour. In addition, user-friendly keys enable the accurate identification of specimens to the level of genus and species. This edition includes expanded information on ecology and the implications of recent molecular research, along with coverage of 200 extra species. The accompanying online material provides a colour photo catalogue, highly illustrated articles and video clips, making this the comprehensive reference tool for both researchers and professionals in the field.