Journal compilation

1 This account reviews information on all aspects of the biology of bracken Pteridium (mainly aquilinum ssp. aquilinum) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communi-ties, responses to biotic factors, responses to environment, structure and physiology, phenology, reproductive characters, herbivores and disease, history, and conservation. 2 Pteridium is a complex genus comprising a number of species, subspecies and varieties. The treatment here is based on a recent revision that incorporates both morphological and molecular data, and is related to its geographical distribution. 3 Pteridium is thought to be a woodland genus, but it can grow in the open. It is cosmopolitan and occurs on all continents except Antarctica. It responds to human disturbance and is often found in open spaces after forest clearance and cultivation. In some situations it can be a troublesome weed, causing problems for land managers. Moreover, its abundance and distribution in Britain are predicted to increase as a result of global climate change. 4 Pteridium aquilinum ssp. aquilinum, the most common taxon in the British Isles, occur