This illustrated publication brings together 20 years of floristic data from the islands of Roaringwater Bay, S.W. Cork, Ireland. A total of 590 flowering plants and ferns have been recorded on these islands. This makes this small area the most plant-rich 10-kilometre square in Ireland. Twelve Irish Red Data book species, over 30 significantly rare Irish plants and several plants new to the Irish flora have been recorded. This is the first Flora for any part of County Cork, the largest county in Ireland, since T. Allin's Flora of the County Cork, over 100 years ago in 1883.