slii INTRODUCTION. 
by exceptional destructive agencies. At present in some of 
the outlying stations of Arbutus, the trees may be counted 
almost on the fingers of one hand, and amongst these trees will 
probably be found one or two more or less moribund examples. 
The range of this species in Ireland would appear to have 
diminished very considerably even in comparatively recent 
times, for its Irish name is found as a component of place- 
names in Clare and even in Mayo, the latter more than 100 
miles north of its present limit. 
In addition to the Arbutus, Saxifraga Geum also appears to 
find present conditions in Kerry unfavourable to its increase. 
In this case it may be that the closely allied and more pushing 
S. umbrosa is crowding it out, or that its place is being 
gradually taken by forms produced by the hybrid union of 
these species and inheriting the more hardy qualities of 
S. umbrosa. 
Before leaving this most interesting group, it may be well 
to repeat that the Lusitanian element in the Kerry flora is not 
confined to the four plants mentioned above. Nearly all the 
species included under Watson’s Atlantic T'ype present in 
Kerry are also abundant in northern Spain and Portugal, and 
probably reached this county with their companions in pre- 
glacial times. Foremost amongst these may be mentioned 
Simethis bicolor which, indeed, would be included in the list 
of plants peculiar in the British Isles to Ireland were it not 
for its occurrence near Bournemouth, where, however, it 
maintains a most precarious existence owing to the spread of 
building operations. It is abundant on the coasts of northern 
Spain and occurs along the western seaboard of France as far 
north as Normandy. Others that may be named are Sibthorpia 
europea, Wahlenbergia hederacea, Trichomanes radicans, &c. 
Like the Lusitanian group, these plants have a markedly 
discontinuous distribution, a form of distribution which is 
generally included among the signs of great antiquity. 
Much that has been already said of the Lusitanian group 
may be repeated for the North American plants present in 
Kerry Sisyrinchium angustifolium, Juncus tenuis, Naias 
flexils and Eriocaulon septangulare. They also show signs of 
great antiquity and of a pre-glacial arrival in Ireland. In this 
case, however, it is the survival of a hardy northern type, not 
of a rather delicate southern group that we have to deal with. 
The line of invasion of these northern plants must have been 
in a direction opposite to that followed by the Lusitanian 
group, and most probably was effected along a coast or chain 
of islands which united Ireland with America through Green- 
