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Chinese. One might fancy on looking at a stone or tree so taken 
up, that one had come upon some fairy inscriptions, and that, 
could the writing be deciphered, they would give information 
respecting the politics or the amusements of the “canny folk.” 
But I must hasten on and draw your attention to plants with a 
different form of thallus. Mingled with the crustaceous species 
already noticed, are others much more vegetable in appearance. 
These also lie flat upon the surface, but are not so closely attached, 
and when moist most of them can with a little trouble be removed 
entire from the substance they clothe. On their under side we 
often observe tufts of fibres which might be supposed to perform 
the office of roots. This is not so, however, and it has been made 
out that their only duty is to hold the Lichen to its support. 
Most frequently thalli of this kind are foliaceous in appearance, 
but it would be a great mistake to consider them leaves. They 
make up the whole vegetative body, and to regard them as leaves 
would be equivalent to making an entire plant to consist of one 
leaf. The popular notion of a leaf is derived from the ordinary 
growths of our trees and flowering plants, and the name would be 
denied to the thorns of berberries and gorse, to the tendrils of 
vetches, and the bladders of the U~¢ricularte, which, however 
different in appearance and use, botanists recognise as modifications 
of leaves. The common opinion, then, that the distinction between 
Jeaves and stems is to be found in their shape and colour, does not 
stand the test of scientific examination, and the only valid distinction 
is one of position. Stems or axes bear leaves—leaves and organs 
of foliar origin are borne upon axes. ‘Tried, therefore, by this test, 
these thalli cannot be leaves, for they form the whole substance of 
the individual plant. 
The number of Lichens with foliaceous thalli is not nearly so 
great as that of the crustaceous kinds ; but even here they are too 
many for me to describe individually, and I must content myself 
with one or two instances. 
The bright yellow Physcia parietina, though much smaller than 
many others, seems to deserve first notice from its cheerful aspect. 
Everyone must have noted it, clinging around farm buildings, 
