514 
Proceedings of the Royal Irish Academy. 
amongst them making hardly a note ; nevertheless more copious 
information about the vertical ranges of the commoner plants in that 
county is desirable. 
The species dealt with in this Paper are those which somewhere or 
other in Ireland reach the altitude of five to seven hundred feet above 
sea-level, or upwards. All those that can only exist below this height, 
even in the most southern counties, are excluded from my list, and any 
that reach it, such as the arbutus, in one situation on the Mac Gilly- 
cuddy's Reeks, are included. Of course those species that can ascend 
a mountain to a certain height in Donegal will be readily conceived 
capable of ascending to a greater altitude in the milder climate of the 
Kerry mountains. The bracken, for instance (one of Watson's 
typical illustrations), has a difference of about eight hundred feet of 
vertical range in these two counties. Our insular climate is too 
equable, however, to admit any very marked and constant difference ; 
and with regard to lowland species travelling upwards the contrast is, 
perhaps, greatest between Kerry and either Down or Wicklow. 
With regard to the Alpine species — those which cannot exist at 
the lower levels, and descend towards the plains only a limited dis- 
tance — these appear to be more constant, and present a wider degree of 
contrast. The mean height at which the Alpine plants which occur in 
Kerry occur also in Donegal will be found to be about eight hundred 
and fifty feet higher in the former district than in the latter, and in 
this direction comparisons and tabulated averages appear to be of 
interest, the more especially as on account of the limited number of 
so-called Alpine species occurring in Ireland, their range is easily 
exhibited. 
It may be asked why I stopped at seven hundred feet, or rather 
why I came so low down the mountains before stopping. It was 
because I believed I observed that height to be somewhere about the 
upper limit of cultivation of grain crops in the mountain regions 
throughout the island, and therefore, above that altitude, weeds of 
cultivation and colonists are eliminated. In Kerry and Donegal and 
Connemara an elevation of seven hundred to eight hundred feet places 
one at once above a host of species properly belonging only to culti- 
vation such as hemp-nettle, dead-nettle, sow-thistle, corn-cockle, corn- 
spurrey, et hoc genus omne. And this height approximates pretty 
fairly to the difference between the north and south of Ireland, if we 
contrast uppermost of lowlands and lowermost of Alpines in each case. 
It is, however, not my intention to endeavour to make deductions : 
certain general laws will be observed to present themselves, audit is at 
