Ixxiv INTEODUCTIOlir. 



is appreciably more abundant in the latter. Similarly, but in an 

 inverse sense, the terms Calcieole A, Calcicole B, and Calcicole O 

 denote the preference of certain species for limestone soils. Such 

 preferences are less frequent and less strongly marked than are the 

 aversions shown by the caloifuge group. In other words, the 

 repulsive influence of lime on one group is much stronger than its 

 attractive influence on the other. The classification of the Irish 

 calcifuge and calcicole species adopted in the text, though founded 

 exclusively on observations made in Ireland, will be f oun.d to agree 

 closely with the results arrived at by Continental observers. 

 Whatever the value of this tentative grouping may be, it will serve 

 at least to draw the attention of Irish botanists to a neglected, though 

 deeply interesting, branch of their science. 



Range in Altitude. — Since the publication of the first edition of 

 this work a large mass of material dealing with the vertical range 

 of plants ia the various mountain groups of Ireland has been 

 accumulated, and this material has been largely availed of in the 

 present edition. For every species not distinctly lowland, that is to 

 say, confined habitually to levels not exceeding 500 feet, the highest 

 observed altitudes in Northern, Middle, and Southern Ireland have 

 been given. Along with these maximum altitudes, the descent of 

 such species to sea-level in North and South Ireland is also stated 

 whenever it is ascertained to occur, it being assumed that a plant 

 which reaches sea-level in the North and in the South, say in Antrim 

 and in Cork, will also reach the same level, in all the intervening 

 latitudes, and, indeed, all round the Irish coasts where suitable 

 stations occur. Plants observed between actual sea-level and a 

 height of 60 feet above it are classed as sea-level. 



For various reasons, chief amongst which are the insufficient 

 height of the mountains, and the rarity and unequal distribution of 

 the Highland type species, eveiy effort to deduce fi-om the Irish 

 statistics, alone, any law of relation between latitude and vertical 

 range of plants seems doomed to disappointment. Nevertheless, the 

 statistics have been rather fuUy given in the text in the hope that 

 they may be found useful for comparison with similar statistics for 

 Great Britain. Three papers have been largely drawn on for the 

 Irish vertical ranges, Mi-. H. C. Hai-t's Range of Flowering Plants 

 and Ferns on the Mountains of Ireland, Messrs. Barrington and 

 VoweU's R^ort on the Flora of Ben Bulben, and Messrs. Stewart 

 and Praeger's Report on the Botany of the Mourne Mountains, quo- 

 tations from these being distinguished respectively by the con- 

 tractions S-art, B.SrV., and S. §• F. In addition to the printed 



