156 THE EVOLUTION OF PLANTS 



ferns in early days, but so there are still, though 

 they belong to different families. 



When we come to the other great classes of 

 the higher Spore-plants there is quite another 

 story to tell. The Club-mosses and Horsetails 

 of our own times are the scattered survivors of 

 what were once great and dominant families of 

 plants. It is only when we have traced their 

 history well back into Palaeozoic times that we 

 begin to realise what Spore-plants are capable of. 



We will take the Club-mosses (Lycopods) 

 next, partly because of their great importance 

 in the Palaeozoic Flora, and partly because 

 they alone, so far as we know, once made 

 a serious attempt to rival the Seed-plants 

 themselves. 



We have already given a short outline of the 

 characters of the Lycopods (p. 137). They are 

 still fairly numerous; 478 species of the four 

 genera are enumerated in Baker's Fernallies, and 

 the number has considerably increased since. 

 I do not include the small family Psilotaceae, 

 which seems to have closer affinities with another 

 class (see below, p. 212). 



The class is divided into two families the 

 Lycopodiaceae with spores of one kind, and the 

 Selaginellaceae with spores of two kinds. The 

 former need not detain us long, for though very 

 interesting plants in themselves, scarcely any- 



