The ‘Lusitanian’ element of the Irish Flora consists of 16 species which share the same disjunct distribution, where the nearest population outside of Ireland is on the Iberian Peninsula. Nick Scott and Micheline Sheehy Skeffington trace the history of these plants and investigate the validity of their Irish native status.
There are only around 900 vascular plant species regarded as native to Ireland, compared to the 1,600 or so in Britain. Along with snakes, moles and several other animals that are common in Britain, the other plant species are believed not to have made it in time before rising seas following the last ice age cut Ireland off, which happened long before Britain was severed from the Continent.