A total of 308 vascular plant taxa are recorded as naturalised on Lambay. Of the 950 taxa recorded for county Dublin, an historical total of 391 taxa have been reported from the island, of which four are probable errors, and 78 were not seen during the present survey. Fifty-four taxa have been recorded for the first time, of which 33 have probably arisen as weeds of agriculture or horticulture.
Comparisons are made between the flora and vegetation today and the two previous surveys published in 1883 and 1907. An analysis of the flora in relation to that of county Dublin and comparisons to other Irish islands are made. Changes in vegetation are recorded, in particular, the decline in heathland, based upon maps and photographs from Praeger’s survey in 1906.