HISTORY OF LICHENOLOGY. 



21 



volunteers are coming forward who esteem it an honour to 

 join this forlorn hope of Cryptogamic Botany, who are eager 

 for the work solely on account of its difficulty. In propor- 

 tion as the Lichens are more fully studied by the reflected 

 light of modern science, — and especially in proportion as 

 their various forms or phases, produced or modified by 

 variations in external circumstances, are carefully examined 

 in different countries and under different climes,— so will 

 the study of Lichenology become more simple and attractive. 

 It will not suffice to collate the characters of species con- 

 tained in the musty folios of celebrated Herbaria; nor is it 

 enough to apply the microscope and chemical reagents to 

 the examination of old and dried specimens. Of observers 

 of this class we have had enough. But the labours of the 

 student must equally begin and terminate on the spot where 

 the Lichens grow; his herbarium and book of reference 

 must be the hill, the heath, the forest ; there he must 

 watch patiently and note accurately — it may be for a series 

 of years — the stages of origin, growth, and decay of species 

 under all the influences, terrestrial and aerial, by which 

 these are so liable to be affected. 



Several Lichens were probably known to the ancients as 

 furnishing valuable purple dyes, and appear to be alluded 



