INTRODUCTION. 3 



not unfrequently to their use in correctly referring some 

 species, hitherto arranged in other genera, to their proper 

 genera, as well as in the detection of new or hitherto 

 unnoticed species. 



The investigation has been rendered comparatively 

 easy through the unbounded liberality and kindness of 

 that distinguished and experienced Lichenologist, William 

 Borrcr, Esq., f.r.s., of Henfield, Sussex, who commu- 

 nicated authentic specimens of most of the plants, and 

 permitted the examination of the original specimens, 

 figured and described in ' English Botany,' and its ' Sup- 

 plement,' and also those of many of the new species of 

 Verrucaria and Endocarpon, discovered and described by 

 Dr. Taylor, in ' Flora Hibernica,' and received from that 

 botanist himself. These were accompanied by valuable 

 remarks and hints, for which the present writer feels 

 dee])ly indebted. 



The dissections were made under a large and poAverful 

 microscope of the best construction by Messrs. Powell 

 and Lealand, opticians, of London. 



The characters and arrangement of the genera adopted 

 in the following pages have been translated, with 

 some slight modifications, from Fries's ' Lichenographia 

 Europaea,' as the latest published work on European 

 Lichens. 



The localities inserted are those only of the specimens 

 which have been used in the preparation of this work. 



