xliv INTRODUCTION. 
The distribution of the 762 plants included in the Kerry 
flora amongst the nine botanical Districts into which the 
county has been divided, is as follows :— 
360, or just over 47 p.c., are known to occur in all 9 Districts. 
48 occur in 8 Districts only. 43 occur in 4 Districts only. 
73 ted 7 ” 30 7 3 ” 
55 9 6 ” 47 2 2 ” 
43 , 5 % 68 =, 1 ” 
Amongst the plants known to occur in one division only, are 
such unexpectedly rare species in Kerry as Ranunculus 
Lingua, Pimpinella Saxifraga, Einanthe Phellandrium, Rumex 
Hydrolapathum, Allium vineale, Lemna trisulea and Pota- 
mogeton lucens, the first four indeed being restricted to single 
localities. 
VI. INFLUENCE oF SoILs ON PLANTS. 
The influence of certain ingredients in the soil on the distri- 
bution of plants has been recognised in a general way for many 
years, and several references to this predilection of plants for 
particular soils appear in the Cybele Hibernica 1866. The 
elaborate researches of Ch. Contejean, which were finally 
embodied in his Geographie Botanique published in Paris in 
1881, however, directed general attention to this interesting 
subject which was first seriously taken up in Ireland by Mr. 
N. Colgan, many of his results being published in Cyb. Hib. 
Ed. II. 1898. 
M. Contejean’s investigations showed clearly that salt and 
lime were by far the most important soil ingredients in regard 
to their influence on the distribution of plants, and that for all 
practical purposes it is the presence or absence of these in the 
soil which is the predominating and in some cases the sole 
influence deciding the presence or absence of certain plants in 
given area. The influence exerted by salt on the vegetation is 
much more pronounced than that shown by lime; and while 
both act much more powerfully by repulsion than by attraction, 
the repulsion exerted by salt is far more general, totally 
excluding a proportion of the flora estimated by Contejean 
as at least nine-tenths of the whole, whereas lime, at the most, 
repels a bare half, a large number of species being quite in- 
different to its presence. 
The influence exerted on the Kerry flora by salt soils has 
already been briefly referred to when treating of the maritime 
plants present in the county, and it now only remains to 
