IV PREFACE. 



Our scope being thus limited, we have endeavoured to include in 

 a compendious form, as much information respecting the localities 

 and range of Irish plants, as can be given within a short compass. 

 On account of the fewness of the observations hitherto made on 

 the upper and lower limits of the elevation of plants, we have 

 preferred to reserve the complete details of this part of our subject 

 for a future edition. And here we would especially recommend 

 this interesting branch of study to those of our botanists who are . 

 in the habit of spending a part of the Summer in a mountainous 

 district. A rough estimate of the upjjqr and lower limits may be 

 made from the Ordnance Survey map, on which the heights are 

 carefully laid down, but it is especially desired that careful obser- 

 vations of both upper and lower limits be taken with the barometer 

 (or sympiesometer) in each of our mountain districts separately, 

 since this is the only way to secure data for a just estimate of 

 the influence of climate on the upper and lower limits of plants, as 

 the " zones " and " regions " in Donegal must range to very dif- 

 ferent heights from those In Kerry or the East of Ireland. We be- 

 lieve that little is gained by the statement that a species descends to 

 sea-level in one district, while it ascends to 3,000 feet in another; it 

 is only by comparing both upper and lower limits "in each different 

 range of hills, or at least in each of the chief groups that any 

 useful results can be expected. The elevation of many species is 

 carefully noted in the MS. catalogue of the Flora of the county of 

 Londonderry, drawn up under the directions of the officei-s of the 

 former Ordnance Survey of Ireland ; and Dr. Dickie's " Flora of 

 Ulster" is another source from which we have frequently drawn— - 

 we can only regret that more details were not given by so accurate 

 and careful an observer. 



For the localities, we have endeavoured to lay the foundations 

 altogether afresh upon recent and reliable authority, having received 

 from numerous correspondents, some twenty tolerably complete 

 county lists. With these we have incorporated most of the sUtions 

 given in the works of Threlkeld, K'Eogh, Browne, Wade, and in 

 the Florae of Lady Kane, Mackay, Power, Dickie and Tate. Re- 

 ference has also been made to many detached papers, and to private 

 contributions which have been furnished from various quarters. 



