Lough Neagh is a freshwater lake in Northern Ireland, and is the largest lake in Northern Ireland. This catalogue is based on the older records from three separate Floras together with recent additions from fieldwork up to 1985. Only naturalised aliens have been included in the Flora proper. A list of aliens which are of casual occurrence, or not yet fully established, together with plants which were recorded in error, are given in the section "Additional Species". Algae and Bryophytes have been excluded.