224 THE VEGETABLE WORLD. 
and these inferior beings were replaced by degrees by vegetable 
species of more perfect structure. All soil primitively sterile, all 
land recently emerged from the bosom of the waters, served first as 
the asylum of crustaceous and foliaceous Lichens ; at a later period 
Mosses and Ferns made their appearance there ; finally, a superior» 
vegetation—namely, the Phanerogames, or Cotyledons—present 
themselves. Everything leads us to conclude that such has been 
the successive series of creations upon our globe, when it was 
sufficiently cooled on the surface to admit of organic life, and 
when the islands and continents were sufficiently elevated above 
the universal ocean of the ancient world to permit them to live. 
Thus the higher orders of vegetables have only appeared, and 
will only continue to make their appearance, upon the débris of 
vegetation of a lower order. : 
But, on the other hand, by one of those striking contrasts of 
which Nature offers more than one example, vegetables of a supeTio® 
order, when they are struck by death—sometimes even during 
their existence—are often the prey of humbler Thallogens, which 
attach themselves as parasites to these princes of the vegetable 
world, and devour them in the end; their destructive action 1s all- 
powerful and everywhere; it respects the works of man no more 
than the works of nature. j 
To produce and to destroy life is, then, the double an‘ 
providential mission which devolves on the Thallogens. Never- 
theless this multiplied work of creation and death is only bestowed 
‘on them on two conditions: the first is an evanescent and soe 
existence, the second is to multiply themselves to infinity ab 
with prodigious rapidity. There are some mushrooms which pr 
duce sixty thousand tetricales or cells per minute ! The capsules 
of certain mosses enclose seeds of which it would require pa 
thousands to make a pin’s head in size. These seeds float free. SE" 
invisible in the air, which is in a sense saturated with them. pe 
In the Cryptogama the reproductive organs in a fundamen 
manner form the phanerogames. Here, without pistil or stamens, 
no ovary, no flower, in the ordinary sense of the word, the yet 
ductive organs which are designated spores are disseminated 2 
most varied manner, sometimes in its whole extent, sometime 
in certain parts of the vegetable. These spores are some _— 
