MOSSES. 55 
operation that goes on in the world ; for in all that 
afterwards takes place there is no such radical 
change, there is simply development into more 
highly organized substance.. Yet in what the 
operation consists, or by what process it is accom- 
plished, is involved in the greatest mystery. 
Mosses are sometimes found in an isolated state 
as single individuals, but they are far oftener 
found in a social condition. It is a peculiarity of 
the family to grow in tufts or clusters, the appear- 
ance of which is always distinct and well-marked 
in different species, and often affords a specific 
character. This disposition to grow together, 
which is exhibited in no other plants so strongly, 
redeems them from the insignificance of their in- 
dividual state, and enables them to modify in 
many places the appearance of the general land- 
scape. As social plants they often cover vast 
districts of land. Along with lichens they give 
a verdant appearance to the desert steppes of 
northern Europe, Asia,and America. Mixed with 
grass they luxuriate in parks, lawns, and meadows, 
particularly in moist, low-lying situations. They 
spread in large patches over the ground in woods 
and forests ; and at a certain elevation on moun- 
tain ranges, they take exclusive possession of the 
soil, forming immense beds into which the foot 
sinks up to the ankle at every step, bleached on 
