288 ECONOMICAL APPLICATIONS OF BRITISH LICHENS. 
use in France of variolarioid forms of Pertusaria communis (genus 
Variolaria of older authors) as a source of Oxalic acid. 
But notwithstanding the possession of such properties and the 
importance of such economical applications, the Lichens have 
always been, and, to a certain extent, still continue, a somewhat 
neglected, and, by many, a despised race; while the sister fami- 
lies of the Crpytogamia have had abundant investigators and 
illustrators. The delicate green wavy Fern is carefully tended in 
Wardian cases in the drawing-rooms of the rich; the beautiful 
red frond of the Rhodospermous Seaweed finds a proud place 
beside the choicest productions of art in the lady’s album; the 
humble Moss has formed the theme of many a poet; and even 
the Fungus has recently had classic words devoted to the descrip- 
tion of its structure or uses; but the puny Lichen, which grows: 
everywhere below and around us in unlimited profusion, remains 
almost unstudied and unknown, its very existence as it were 
ignored, ; 
Our chief grounds for recommending the study of Lichenology 
to the consideration of the observances of nature’s phenomena 
are— 
1. The easy accessibility of the objects of study; and 
2. The inexpensive nature of the study itself from the simpli- 
' city, or, it might almost be said, non-necessity of apparatus for 
observing, collecting, and preserving. 
The Lichenologist is not compelled to make expensive or dan- 
gerous excursions to foreign shores: his field of investigation 
surrounds his home wherever that may be; it is alike productive 
and of easy access. From our sea-coasts to the pinnacles of our 
loftiest mountains Lichens abound everywhere ; so common in- 
deed and so familiar are they, that the very idea of examining or 
collecting “ time-stains” from our rocks, walls, or trees will by 
many be ridiculed as frivolous and absurd. Nor is there a neces- 
sity for complex instruments or apparatus. A few pill-boxes, an 
old knife, a simple pocket lens (and, if possible, also a micro- 
scope) for examining, and some paper, cardboard, and gum or 
glue for preserving, constitute his whole armamentarium. 
Let it not be supposed however that the investigation of spe- 
cles 1s correspondingly simple or easy. No plants present a 
greater variety in external form, dependent on slight changes in 
external circumstances: the same species frequently exhibits an 
