xxiv INTRODUCTION 



The flora of the Central Plain is essentially calcicole. The soil 

 of the drier cultivated tracts is usually calcareous. The marshes 

 are more so, and are underlaid with a tough grey limestone 

 mud. The eskers are formed almost entirely of limestone debris. 

 The bogs form a notable exception, their surface being cut off by 

 the thick layers of peat from the limy materials on which they rest. 

 The plants which grow in the bog-pools — even Charas, which have 

 a peculiar faculty for collecting lime — are quite free from the 

 incrustation which, from the botanist's point of view, so often 

 ruins aquatic ;- plants in limestone districts. The characteristic 

 plants of the Central Plain are largely inhabitants of the abundant 

 marshes and bogs. The subjoined list will exemplify the nature of 

 the flora : — 



Chaeacteeistic Plants of the Central Plain. 



Pastures and dry ground. 



W 



W 



Ponds and ditches. 



EanuncTilus circinatus. Cladium Mariscus. W 



Utricularia intermedia. "W Chara polyacantha. 



Potamogeton plantagineus. 



In the above list, the plants marked W become more abundant 

 in the western portion of the Central Plain ; those marked E are 

 more frequently met with in suitable habitats in the east. 



As in the west we find alpine and northern species descending 

 to unusually low elevations, so in the Central Plain and in the 

 north and south we may trace a tendency in the flora to the same 



Carlina vulgaris. 



E 



Orchis Morio. 



Orchis pyramidaKs. 





Bogs. 



Drosera anglica. 





Ehynchospora f usca. 



Vaccinium Oxycoccus. 



E 



Ehynchospora alha. 



ArLcLromeda Polifolia. 



E 



Lastrea spinulosa. 

 Marshes. 



Galium uliginosum. 





Carex fiHformis. 



Epipactis palustris. 





Carex paludosa. 



Juncus obtusiflorus. 



W 





