182 
THE FAIRY-LAND OF SCIENCE. 
them with the stems of living plants, while the fruits 
c c and the little round spores lying near them, tell 
him their history as well as if he had gathered them 
from the tree. In this way we have learned to know 
very fairly what the plants of the coal were like, and 
you will be surprised 
when I tell you that the 
huge trees of the coal- 
forests, of which we 
sometimes find trunks 
in the coal-mines from 
ten to fifty feet long, are 
only represented on the 
earth now by small in- 
significant plants, scarce- 
ly ever more than two 
feet, arid often not many 
inches high. 
Have you ever seen 
the little club-moss 
or Lycopodium which 
grows in bogs, swamps, 
and moist woods near- 
ly all over the United States, from Lake Superior 
to Virginia and Carolina, on heaths and mountains? 
At the end of each of its branches it bears a cone made 
of scaly leaves ; and fixed to the inside of each of these 
leaves is a case called a sporangium, full of little spores 
or moss-seeds, as we may call them, though they are 
not exactly like true seeds. In one of these club- 
mosses called Selaginella, the cases B near the bottom 
of the cone contain large spores b, while those near the 
FIG. 52. Selaginella selaginoides . 
Species of club-moss bearing 
two kinds of spores. 
