112 TEXTBOOK OF BOTANY 



certain species of the present day ; some of these grew to be 

 large trees. There were other tree-Hke forms, some related 

 to the horse-tails and some to the club-mosses. There were 

 also plants which had fern-like leaves but produced true seeds ; 

 and these fossil plants have taught us much of the way in 

 which some of the living seed plants have developed from the 

 ferns. 



