HORSETAILS AND CLUB-MOSSES 201 
During the Coal-measures the club-mosses occurred in 
great abundance, and among them were large trees of vari- 
ous kinds, forming a very prominent part of the forest 
EK 
Fic. 193.—Lycopodium: A, the whole plant, showing the horizontal stem giving 
rise to roots and erect branches bearing strobili; B, a single sporophyll with its 
sporangium; C, spores much magnified.—After Woss1DLo. 
vegetation. As in the case of the equisetums, therefore, 
the club-mosses, or Lycopods as they are called, were once 
