212 REVIEWS. 
fructification is of two kinds. First, it exists in various kinds of 
receptacles all comprehended under the general term Apothecia 
(amo, from, @yxn, a depository or partial receptacle). These re- 
ceptacles are either like little shields, as in Parmelia, little cups, 
targets, buttons, tubercles, etc. Second, the fructification often 
exists as masses of a powdery substance, either in indeterminate 
forms or combined into more or less evident receptacles. 
These plants form a considerable branch of the vegetable king- 
dom, and have a very important part to perform in the economy 
of nature. They are the first vegetable beings that clothe the 
bare rocks, and extend generally to greater altitudes than other 
plants; hence, by their partial decomposition, a soil is prepared 
for the growth of plants of a higher grade. They may be called — 
the pioneers of vegetation, always advancing im the van and pre- 
paring the way for more important productions. Some of them 
are valuable as esculents: the Iceland and Irish Moss recom- 
mended by the faculty as very nutritive and light food for the 
sick and the convalescent. The Reindeer Moss, which is so 
abundant in the northern parts of Europe and is not unknown in 
England, forms, as is well known, the food of the reindeer, the 
Laplander’s wealth and pleasure. Their value in the arts is still 
more considerable than their dietetic utilities, to us at least. 
Some of the most beautiful and costly dyes are derived from 
Lichens: on this head we refer our readers to the valuable 
papers by Dr. Lindsay, abstracts and notices of which have ap- 
peared from time to time in this Journal. 
We hope our readers will excuse this long, though, it must be 
admitted, rather meagre account of a tribe of plants which are 
barely known even by name. Most people know Ferns by name, 
many know Mosses (Musci), and every one knows a toadstool ; 
Seaweeds (Marine Alge) are also generally recognized ; but we 
have scarcely ever met any one except a botanist who knew any- 
thing about the greyish, yellowish, whitish bodies that hang 
from trees. The more highly developed forms are called by the 
unlettered, Mosses, for want of a better name. The crustaceous 
Lichens, whether growing on wood, bark, or stone, etc., are, we 
believe, universally considered as mere modifications or parts 
(altered somewhat by exposure) of the rocks, trees, or other sub- 
stances on which they are produced. 
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